According to his book "Aiming High", Jon Johanson (flew around the world twice in an RV-4) installed a Velo Seats molded racing seat in his RV so he would be more comfortable than the stock seat. Must have worked for him.
The beauty of homebuilts though, try anything (safely). If you don't like it, try something else. Safely.
RV-4 N249P O-320, Dual P-Mags, Warnke Prop, GRT Sport EX