If it were me and I was wanting to go glo, I would probably lean towards 15 size engines. My B17 has a 124" wing and calls for 4 40 size glo. The engines have a carburetor, so you will have to set up a linkage rod to adjust the speed manually and lock it to open once the engine is started and open to full.. Maybe consider using 2, 40 size on the outboard nacelles and static "fake" looking engines on the inboard since it is a control line . Multi engine models can be complicated.