You might want to bench run those motors first to see if you are going to like them. I had really bad luck with my only MVVS engine, and ended up trading it to MOECA for one of their motors. I've not read any good stuff on them either, but check around first. R/C Report really trashed them, and not the only folks to do so. You will need dependable engines on a twin, or you will lose your model.

Bench run the engines and do so until you can hold a peek rpm (or a touch rich in peek) with out over heating, and also have a solid idle. A good transition is needed also with a twin, three or four banger. After you are satisfied each engine is running good, I put mine on an engine stand together, hooked up to a common throttle, and run them that way to see what I have (I check peak RPM, over heating, idle and equal transition). Getting all the problems ironed out prior to installing them is important. Then setting them up is the next chore, and take time to set up servo arms, cables ect. as even as you can. I put easy connectors on my carbs. so to make easy ajustments. I also make sure my servo arms line up equally and install my throttle push rods evenly and the same way-you will be surprised at the difference between servo's, even good servo's. I learned the hard way, and even have had to cut into my wing to re-build my throttle servo linkage on one of my first twins. I now run one servo to one engine...accept on my small model twins, and that is for weight savings. I also had a cooling problem with one model that I no longer have...for I stuffed it in with an engine failure-so nacelle aerodynamics is important too, even after a good break in-but if you run with your engine heads in the wind, little or no problems here. So even if all goes together well, test run your model for several tank fulls on the ground first. You can time your engine burn at full throttle, and set up your radio (if you have a timer), to let you know when you have low fuel to land your model. Dead stick twins drop like rocks, and with out the tail feathers in the prop blast, less authority in this flight area too.

I never detune, or tweek my engines to eachother...never. I run each engine by itself, and set it to itself to run it's best. Then tack the engines and listen. Listen to what you have, and use your tack. Just thoughts on what I've learned the hard way over the years...

Multi engines are sweet music, and always grab attention, not to mention just plane cool...

Soft landings always,

Bobby of Maui