I used t-nuts in my engine mount so I don't have to worry about access for holding a hex nut. There is just enough room to slide the engine in and out. I secured the engine with allen-head bolts. The cowl is glued permanently to the fuselage. I plan on doing it again on my next kit, a highly modified, scratch built 4-star. This time I am going to add something to make the bottom of the fuse a little more round and maybe increase the curvature on the top. This will make the cowl look a little better I think.