I would suggest you leave the cowl off for a while, to get to know the engine a little AND too make sure nothing you have going on with the cowl is making it overheat. The experience of running without will let you know about any issues right away when you put it on. The idea of blocking the one side is probably a good one.

I have this same combo ready to maiden, but I went with the engine on it's side and a Bison Pitts muffler. Not sure I would do that again because the engine sits very high within the cowl. We'll see how it all works out.

Mods include rudder servo in back (for increased options when it comes to setting the CG), and carbon fiber tube installed in the really soft alum. struts. The rest of the package all looks good. It's right at 7lbs ready to go. Looking forward to the chance to maiden... -Al