(EDIT: Ringrush) had the idea to use a talon trot "skid" to rejump and get to the Clanker's Cavern puzzle portrait to open the world early without shock jump. This should save a bit of time in 100% if possible.
I got within about 1 frame of making the jump successful, but it's extremely tedious to perfect. I feel like it should be possible with a perfect angle.
I theorize that you need to initiate the rejump between about 636 and 645 Z coordinates. The angle you're facing is really important, and the spinning camera makes this terribly difficult to optimize. There are two different frames on which you can beak with promising results, I would try both of them.
If you jump from closer to the door you'll have a higher Z coordinate. If you jump from further from the door, you'll have slightly less X and Y distance to cover. The height of the platform is 700, I believe you can beak up there as long as you're above about 660 Z height.
This is one of my better attempts:
http://www.mediafire.com/download.php?m8iiaz7igz0zax2
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Cronikeys also had the idea to get OoB after filling in the Click Clock Wood puzzle to open the world. This would warp you back to the pipe in the room with the 180 note door, saving about 15 seconds. If you can jump high enough to land on the cut branch on the tree near where I jump in the following video, you can easily get out of bounds over the top. Again, I was just short of getting enough height to do so.
Here's my best attempt:
http://www.mediafire.com/?sap47r1b6gzahzu
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Memory Addresses:
XPosition: 00C67C98
ZPosition: 00C67C9C
YPosition: 00C67CA0
XVelocity: 00C67CB8
YVelocity: 00C67CC0
ZVelocity: 00C67CEC
JiggyAmount1: 00C71A48 (for reference)
JiggyAmount2: 00C71A5C (for reference)