Too many people buy these old engines and compare them to modern equivalents. Break them in as they should be, run them as they were intended, and enjoy them for what they are.
Many of us experienced Berkeley kits that were known for ill-fitting parts. I have had good and bad. Someone once referred to Berkeley kits as a box with good plans and a random assortment of balsa. Your pics seem to show good fits...many replacement parts?
Re the PAA loaders. Pan American Airlines once sponsored a Nationals 1/2A FF event. I THINK there was a required weight (load) and folks would try to design planes that would stay up longest. Perhaps someone remembers all the particulars.
George