I would use the OS FP or LA series of engines, they may not have quite as much power as the Magnum but they are much lighter. I would guess that the OS .15 is about the same weight as the Enya .09, I love Enya engines but some of them are a bit on the heavy side.
I also find OS and Enya carbs to be the best in the industry, easy to tune and reliable. The Magnum carbs can be inconsistent, some OK and some horrible.
I gave up on a recently purchased Magnum .15, never could get a reliable idle. Only the second or third engine in my 50 year modeling career that I can ever remember giving up on. Sold it on Ebay and yes I mentioned my problems in the sales listing.