RE: Top Flite Giant Mustang
Here's a shot of the P-51 earlier in the build with the US-41 installed. Note how small the extrusion is outside the cowl.
The Da-50 made the hole bigger, but only sticks out about 3/8 to 1/2". I literally bolted it to the same Great Planes soft mount that the US 41 was on.
Hope this helps.
greg
PS The gear doors are driving me bonkers, but will be worth it.