4-40 rod conversion is a must, i have all hitec 425bb and one 605 mg on rudder and have no had a problem. I would not use 3003 because they are NOT bb, al least use 3004......if yo want to knife edge and flat spin y need the hi torq (605) on the rudder.

I have a saito 100 in it and it is great, i would recommend at least a 75 - 90 2 stroke or 91-100 four, anything less and you defeting the purpose of the air plane.

if you can afford hi torq all the way around go for it, but IMO it is not needed.

......put your 60 in a cub or something.....ha ha