I have an alternate suggestion for you! Buy some 3/16" Aluminum cut to a length of 2" and a width of 1/2". either bolt you engine of choice to two of these strips, top of motor mount and bottom motor mount by tapping the holes to a 4/40 thread and then mount this assembly to the profile fuselage by threaded inserts held in with epoxy. Safe system to do this is use a 3/8 long cap screw, dipped in vaseline as a release agent, drill an appropriate hole for the insert, screw in the insert with an allen wrench, let cure over night and then bolt the engine, strip assembly to the inserts! You'll need four inserts and the holes must be drilled in the strips so that you may bolt the assembly to the plane! I've used this method on engines up to and including ST .46's so far. Hope this is clear for you.
Phil Spillman