Tommy
A few points that may help you.
I used the Robart retracts and they work very well. You do however need to modify the nose gear mounting from the angle shown on the plan to get the wheel inside the fuz. I used Eurokit wheels and brakes and had to change the bushes in the wheels as the Robart axles are 1/4" and the Eurokit wheels are 6mm.
Don't know if you intend using the fiberglass fuz or not but if you do, you should make the rear former that goes up infront of the tailplane out of good quality ply as this carries all of the twisting loads from the tailplane. I would also suggest glassing it into the fuz with some tape. Mine broke some of the glue join during test flights. Luckly it is easy to repair through the tailpipe opening.
Hope you have fun as the model flies very well.

John