Roll Center design theory

[Salt Racer]

...I'm presently doing 2D sketches in Solidworks to get my design started. My figuring is that eventually I can flesh out the structural design in 3D. Is this a good idea?....

Yes, but think of it as only a part of suspension design. When I design scratch-built suspension, I constantly go back and forth between suspension program and drafting or solid modeling software once basic parameters are set (tire size, rim offset, LCA length, etc). Watch for John Parsons' article in May issue of PHR.

...It shows how little change change to x,y,z numbers results in substantial change of different angles. IE, just an inch of chassis drop can totally change the handling characteristics...

Yup, that's why it's important to evaluate the modification on geometry before you actually make the physical change. It's so easy to overdo something.

...I'm using different figures though since I'm anticipating a higher pin height on the B- body spindle (+1in I think)...

This may or may not be the case. I don't know exactly what kind of spindles Dennis had, but it needed 3.0~3.5" drop to make LCAs level. I doubt you're planning to use 23" tall tires. Better get the parts in your hand before you finalize the design.

...Raising the spindle more and more will shorten it. This would be the general trend for any setup given this case, no?...

Assuming you're talking about raising UBJ, then yes. If you're talking about raising the whole spindle (w/o changing its height) relative to the chassis pickup points, that would be generally yes also.

...In fact, I once saw one of the nationally ranked mod drivers lose his left front tire due to loose lugnuts. He completed the entire heat (10 laps on a 1/2 mile) and kicked everyone's butt doing it. Yeah, he's good. He had some dirt packed in his LCA though :-)...

That is just too cool!! Having good suspension helps, but it all comes down to driver's ability in the end.

...Another important note is that we don't get to 0 bumpsteer, just tolerable limits...

That's what I do too when I'm just modifying what exists.

...When you guys talk about RC migration how much do you personally like to see on a full body car?

No more than a couple of inches. Less than that on paper or computer b/c more than likely the finished product isn't as dimensionally precise as what you intended.