I've never had luck with inverted engines. They never start, flood easily and won't stay running.
I have an OS 45 that I might use or I might buy the Saito 56.

I might try to run my OS on a test stand and see if I can get it running to my liking before I put it in the fuselage.

I read all the threads about the aresti. Mine came missing the elevators. I called New Horizon and they are sending out a new tail kit.
Leo