My YS63 is only around 17.9 oz including muffler. With the extra 3 oz, you may have a challenge I didn't face in moving the battery much further back behind the servos perhaps, unless you want more tailweight plus a heavier plane. I added 1 oz of tailweight to get to the rearmost CG, 4-1/4".

Assembly, it goes together very well, with a very well written manual. Excellent parts fit on mine.

Because of the narrow fuselage, the is no room behind the firewall for one of the blind nuts for the motor mount. A wood screw is supplied for that 4th hole. I selected a Great Planes medium adjustable motor mount, since the bolt pattern is smaller than the stock motor mount. Therefore I could use 4 blind nuts. You could also select a Dave Brown mount if there is one that fits your engine. Note, the firewall to thrust washer distance is pretty big, so you will need a long mount. You will need to drill new holes through the supplied wedge-shaped thrust plate to accomodate your new motor mount.

Unusual for me building an ARF (maybe my 20th ARF?), I was able to use all of the hardware supplied, including the pushrods, horns and tank. I never use ARF fuel tanks. This one was sweet. I chose not to use the nylon clevises, but opted for the Dubro composite ones instead. These are the black nylon ones with the brass plated pin, and the sliding lock retainer for the pin. Nice.

If you fly off grass, you will probably want to upgrade the wheel size. I went with 2-1/2" (the largest I could fit in the wheel pants) lightweight wheels.

That should get you started.