I'd leave the vinyl top off otherwise sounds great! Keep the pic's coming.
If it were me, I'd leave the vinyl top off as well, especially after seeing firsthand the horrendous amount of rust that will form eventually, due to trapped moisture under the vinyl. But, build it however you want!
it would be different if the car was going to be a daily driver. fact is the thing will probably be trailered every where and just sit in a garage when not on a trailer or show field.
If it were me, I'd leave the vinyl top off as well, especially after seeing firsthand the horrendous amount of rust that will form eventually, due to trapped moisture under the vinyl. But, build it however you want! 
