A FPV Pietenpol would be a neat project! One recommendation though on making it pleasant for FPV: make sure it has ailerons for proper roll control. One thing I notice flying FPV vs LOS is that flying coordinated is paramount to have a pleasant, realistic in-cockpit experience.
We don’t notice much adverse yaw, skidding and slipping flying LoS. But it is very prominent in a FPV plane. And having the nose drift around using skidding to bank, as would be the case in a three channel plane would make it disorienting from cockpit view.
Good excuse for me test it out on a Pietenpol. Challenge accepted