Well just completed my new project. It is a telemaster with 4 .25 size engines. It has taken me about 100 hours to complete the conversion. Some of that time was rebuilding the airframe. It was a crashed wing that was beat up pretty bad. The engines are 2 .25 OS fx's. one .25 OS la and one .25 Magnum gp. I did not even try to sync the engines before the maiden flight. So will it fly? Here is the maiden attempt video:

http://s2.photobucket.com/albums/y47...rmaster096.mp4

looks like it was fun!

Nice going. Congratulations. It is looking pretty good.
I always adjust each engine on a twin or multi-engined plane to run its best, at what it is happiest with for needle valve settings, etc,
As long as the engines aren't too far way from each other RPM-wise, it'll work Ok. it'll just be a little trim adjusment.
Now granted you don't want them way off from each other. But fortunately you have some leeway there.

I put four matched OS .25FP's on a Tower trainer... It flew but was way to heavy for the plane, I guess interesting is a better description. After two flights I took the motors off and binned the airframe. Yours flew much better, congrats!