I did not fly mine with gas but I did fly mine with a OS120 FS 4 stroke and I added a 1 oz spinner nut I believe and it flew great for me. Everything was factory on mine absolutely no upgrades for my Gee Bee. I had too many flights to count. I did fly off of asphalt so that may have been the reason for me not having to beef up the landing gear. I know you are not wanting to fly nitro but you can take my feedback on the balance of mine to help with the input Foodstick provided above.
As always take a video.
If you need any inspiration here is a video of mine
https://www.youtube.com/watch?v=GWSW5RhO5E4