Well, I was looking for a GM- Chevy Tech SHeet I have about, trimming down the STD or NON-Z22 (RS) PN#'d Moulding (Front) Part to meet the three pc lower trim.
I think there is discussions on this topic- (Search) i think Ed had great #'s
For Me; I bought GM mouldings from Classic Camaro (1980's) & they were out of the Z22 fronts and substituted the full arc Front and I got them to fit fine w/ the three pc lower trim, It looks goofy but 99.9% folks do not notice. (*My rears are GM Z22) & stop at rs rocker trim.