Yes I think that the PAW .60 was more for slow flying planes, trainers, old time models, free flight and such. It has a small intake that limits performance, but a small intake has a stronger fuel draw too. Keeping the power down also helps it to be more quiet too. Slower propeller speeds reduces noise as well. Also it should have really good fuel consumption rates and be something of a miser for consuming fuel. So it won't be a high performance engine. But it should be easy to start and run though. That may make a lot of people, especially beginners happy. I think the PAWs should probably be better compared to the old vintage spark ignition engines made up until the 1950's.
The higher performance diesels were likely the ones that MVVS made. MVVS has made large displacement diesels and those should develop much more power. But more power means more fuel consumption. The high performance diesels tend to consume fuel at higher rates, more like glow engines. They also make more noise and turn props faster that make more noise too.
Davis Diesel Development offers some diesel heads for converting engines. DDD has made heads for many engines over the years too. So usually one can see a DDD head pop up for sale here or there for different engines.