Shovel,
When I first started with WDL I had tremendous difficulty wrapping my head around all this vector stuff. I believe I can help you understand some of these problems. I've encountered some of them in my own work. If it's any consolation, It does get easier as you do it more...
VEC_NORMALIZE "Chops the vector to the length given in the second variable while keeping it's direction".
I can't define it any better than that quote from the manual, but I can give an example that may be helpful...
In the SpaceFlight workshop, I have a variable for a spaceship called "MAX_SHIP_SPEED". The idea is that your ship can't go any faster than this speed. Once I apply all the accelerations and things to the direction that the ship is going, sometimes the ship is going faster than my speed limit, so I "Chop" the size of my speed vector down to the size it is supposed to be by using Vec_normalize, and it still retains the direction that it initially had. I use it as a speed govener.
Your next issue, with wobbly wheels might be if you are adjusting the pan, roll and tilt of the wheels directly...
The tilt value of an entity can never be greater than 90 or less than -90. If you give an entity a tilt value of 100 for example, the engine will account for that by flipping the PAN angles 180 degrees and then adjusting the tilt to (180-tilt).
I know that sounds crazy, but it's true. From the TILT point of view, everyhting is ok, from the PAN point of view everything gets messed up when you have a tilt larger than 90.
If you need to make those kinds of changes, you should use the ROTATE command instead. (NOT the VEC_ROTATE command, that does different stuff!) ROTATE somehow knows how to fix the problem using a different kind of math called "Quaternions".
Can't really help you with your third question, but I help this other stuff gets you going in the right direction. Good luck!
-WildCat
[This message has been edited by WildCat (edited 01 June 2001).]