It IS covered in the thread, he assigns each possible height for the lava a number from 1-9, explains them each in detail (hell 1 and 2 are practically the same but he distinguishes between them anyway lol) and then gives the order of the heights over an 8-minute interval (cause tourney matches generally have an 8-minute time limit) and emphasizes on the more important ones.
And yes the heights are slightly random in that they're not always exactly the same height (they will vary by a few 'centimetres', if you will) but the variation in the heights is pretty much negligible.
[COLLAPSE="Read it you scrub"]Level 1 / The Bottom: This is the state the stage starts in. The acid is down as far as it can go, far below the chain in the lower right. (I use this as one of my primary visual cues for the level.)
Level 2: Up a bit higher than level 1, with most of the chain submerged, but NOT the right corner where it attaches to the wall. This is important, because you will not be saved from the blastzone at this point.
Level 3: Only slightly higher than Level 2, ALL of the chain is now submerged, and this is the first level at which the Acid WILL save you, you will contact it upon entering the magnifying glass. Alternate visual cue: Comes up to slightly below the "x" in the crossed cables.
Level 4: This one is the first where the acid is actually visible from a direct vertical perspective. It comes up to the "X" in the crossed cables in the mid-left section of the stage. Covers the blastzone and nothing else.
Level 5: Comes up to the bottom of the stage, causing it to steam. This will hit Marth if he is hanging on the ledge, since he is a tall character. Smaller characters are not affected.
Level 6: This can vary slightly, but I classify it as when the acid covers sections of the main stage. This is SOMETIMES safe, since patches do not get covered, however, this appears to be slightly inconsistent. The safest spots are directly under the main platform, and of course, on top of the platforms.
Level 7: Covers everything but the platforms. Self-explanatory.
Level 8: Covers the right platform, and patches of the left.
Level 9: Covers everything but the top platform.
(no pic)
What all this boils down to is that the acid has to be at LEAST level 3 to cover the blastzone, level 6 to hurt you on the main stage, and level 8 to hurt you on the platforms.
I did a couple sample runs to test the pattern and timing. This is one of the more accurate ones:
Bottom (8:00), 1 (7:44), 4 (7:34), 2 (7:26), 5, (7:20), 1 (7:13), 8 (7:08), 4 (7:03), Bottom (6:52), 3 (6:45), 1 (6:36), 5 (6:27), 6 (6:18), 1 (6:10), 6 (6:05), 5 (5:58), Gradual decline to Bottom (5:44), 1 (5:27), 4 (5:19), 3 (5:12), 6 (5:05), 1 (4:57), 8 (4:51), 4 (4:42), Bottom (4:38), 3 (4:30), 1 (4:19) 5 (4:11), 1 (3:56), 6 (3:51), 5 (3:46), 4 (3:39), Bottom (3:30), 1 (3:20), 4 (3:10), 6 (2:56), 1 (2:48), 6 (2:43), 4 (2:36), Bottom (2:27), 3(2:18), 1 (2:06), 5 (1:58), 1 (1:43), 6 (1:37), Gradual decline to 4 (1:25), Bottom (1:16), 1 (1:05), 4 (0:52), 2 (0:44), 6 (0:39), 1 (0:32), 9 (0:26), 4 (0:19), Bottom (0:11), 3 (0:06), 1 (0:03)
Complicated and hard to read, so I'll highlight the important stuff.
8 (~7:08) - Only parts of the left platform, and the top, are safe.
6 (~6:18) - Will cover the bottom part briefly, then recede.
6 (~6:05) - See Above.
6 (~5:05) - See Above.
8 (~4:51) - See Previous 8.
6 (~3:51) - See 6.
6 (~2:56) - See 6.
6 (~2:43) - ...
6 (~1:37) - ...
6 (~0:39) - ...
9 (~0:26) - This one is volatile and dangerous. Sometimes it's an 8, sometimes it doesn't happen. Be aware of it, especially if the match is down to the wire.
TL;DR version: Watch out for lava at 7:08, 4:51 and 0:26 ESPECIALLY. Read just above for more times.
Important disclaimer again: THESE TIMES MAY VARY SLIGHTLY. PAY ATTENTION.[/COLLAPSE]
The pink. LOOK AT IT.
And the lava stops when it gets to its predetermined height.