I am going to build one over the winter. It's my intro to pattern planes.

I will use retracts. I'm thinking I'll mount the engine on its side, or at ~45 degree down so that I can get the muffler out the bottom..... that plan may change when I take a careful look at it.... it may intrude into the tank compartment too much. I want to leave open the option of retro fitting a tuned pipe, hence my desire to get the muffler out the bottom.

And... to feed my insaitable desire to complicate matters, I'm going to experiment with a tank over (or nearly over) the c.g.... but I'll build it so that I use the conventional location as well. It looks like you can squeeze a round Sulivan 10 oz tank under the canopy. That will put it just ahead of the CG.

I fully expect to have a blast....

Did you read the reviews on GP's web site?