Sounds like a cool car Greg, do you have a build thread or any pictures of it posted anywhere?
Regarding caster, I see no ill effects during street driving from the amount of caster I run...many newer cars run similar caster numbers straight from the factory. If you had manual steering with no power assist you may have some parking lot issues but other than that...I say caster away!!!
Thanks Lance it has been I fun project. No build thread or posts...it was a bit of a lone wolf / internet stalker build. I am just now starting to meet some people with similar interests.