A lot of what I said in the last post still applies here: wide use of varied tones, the occasional fading out of foregrounds (4.19.62, when Sanzo is watching two characters talk and getting suspicious), use of bleeds or borderless panels, and generally-improving depictions of characters. (There are a bunch of great comments in the prior post, which I highly recommend.) I'm going to talk here about four things: one really complex page; two really simple and forceful pages; some parallel page structures; and a couple examples of recurring images.
Still major spoilers for volume four (and a small spoiler for volume seven); and still don't spoil me for Gaiden or Reload.
(I should note that the scanlation images have been saved at 50% quality to reduce their size.)
Page structure: complex
First, here's 4.18.20, a very complex page, possibly the most complex in the volume: and yet it's so carefully structured that even a moment's worth of examination will reveal what's going on. Here's a half-size unmarked version (original size)
The first thing that grabs your eye is the big text balloon, outlined in heavy black, in the top right corner; next is the similar balloon to the bottom left of the panel (the dark of the toy's tunic and of Hakkai's hair reinforces this). On the way, your eye passes the mahjong tile (which Tokyopop helpfully translates as "grudge"), and then is drawn back up and to the left by the black of Hakkai and Gojyo's hair, stopping at the whitesace of the next speech balloon. (This picks up on what 
telophase said in comments to the prior post about how the visual flow is designed to make you look at the art as well as the text). The rest of the path down the page is pretty clearly marked by the faces and the text balloons (and even the path to the next page is marked, by the toy's looking off to the left).
The top right corner, which is very crowded, is nevertheless carefully organized. The ivy on the top and the bottom (which might be a reference to Hakkai's youkai form, per volume 7, though the images aren't that close) "border" the panel, and run in the direction of the visual flow: the top parallels Chin Yisou's shoulder and the speech ballons, and the bottom parallels the toy's elbow and the subsequent speech balloon. The background of Chin Yisou and the toy tells us who sent the toy. It also works with the visual path: Chin Yisou's light-colored shirt is on the left, where Gojyo and Hakkai's hair will stand out against it, and his stick-things (what are those?) in his mouth also point down and to the left, as the ivy, the text balloons, and even the top of Gojyo's hair all do.
I've marked the visual path in red below, and the ivy borders as blue (I've also edited the last post to use a consistent color scheme).
Whew. At less length now, I promise.
Page structure: simple
This is the climax of the Chin Yisou arc, and they're just such cool examples of movement that I couldn't resist putting them up. First there's the double-page spread of 4.22.150-151 (original size):
And then you turn the page to 4.22.152 (original size):
Do I even need to say much about them? The two shots of Chin Yisou's face in the double-page spread, with the black balloons, his hair, and the spray of blood, all run hard to the left—which is good because, especially in the Tokyopop editions, it's hard to see the bits of light outlining Hakkai's arm (they get kind of lost in the binding, though admittedly I try not to crack my books' spines). Then the whitespace between their bodies, and the white speech balloon, bring the eyes back down and right; and from there it's a (rare?) linear run to the left. Like so:
(I apologize for the terrible hand-drawn curve; GIMP's curve drawing tool frightened me badly.)
And the next page, well, that's about as simple as you can get: straight down and then hard left. Hakkai's hand, Chin Yisou, and Hakkai's sash and pants all set up a strong light-colored vertical line (marked in blue), which is echoed by the speech balloons; and then the dark of Hakkai's arm and the blood pull the eye sideways.
(And then, because I can't resist, you get courteous humorous Hakkai just three panels after, reacting to Chin Yisou's declaration of disappointment.)
Page structure: parallels
There's a repetition of a panel layout early in the volume that caught my eye, on 4.18.16 and 4.18.21 (original sizes):
First, these take good advantage of being in the woods: the trees in the background emphasize, on one hand, Hakkai's standing, and on the other, the looming over the toy (thanks to herchuckness for remarking on the surroundings, which reminded me to notice this). They also have one important statement on the tall panel, and then the shorter panels indicate the passing of time as Hakkai processes the statement and comes to a decision by the end of the page. They're only separated by four pages, so I suspect the similarity was meant to be noticed. (See also 4.22.136 and 4.22.138, which are Hakkai puppetry; and 4.18.31 and 4.18.39, which bookend the Gojyo-seed episode and puncutate the theme of Chin Yisou's trying to break Hakkai.)
There are probably other panel-layout repetitions in the volume, but these are particularly easy to notice because they're so distinctive.
Recurring images: hands and eyes
It's obvious that hands and eyes are the recurring imagery of this arc, just by reading the text. There a couple of things I wanted to point out about this visually. First, I think it's notable that during and after the transformation in the dungeons, the only glimpses we see of the reborn youkai's form are first his eye, and then his hand in silhouette, in panels 2 and 4 (4.22.133) (original size):
Also, when Chin Yisou starts disintegrating, his right eye goes first, and we get a two-panels-across, one-person-per-panel layout of him and Hakkai; and the next panel is of Chin Yisou's hand in Hakkai's (4.22.155) (original size).
Finally, when Chin Yisou first comes onstage in flashback, he doesn't get any eyes until for several pages: he first appears on 4.21.109, and his eyes are obscured on way or another until 4.21.114, when he describes the legend of humans and the blood of a thousand youkai:
After that, he next appears in the present on 4.21.123, and spends that page and the next page and a half without eyes again, until they open on his trying to take over Hakkai's heart (4.21.125):
I conclude that somewhat like Hakkai, when Chin Yisou is looking straight at you, it is Bad News.
And that's volume 4.
[ more Saiyuki art commentary ]