Recently, I started designing a replica of the Tupolev Tu-16 bomber. The plane has mostly been working well until I ran into some issues with landing gear. The landing gear I'm trying to make is supposed to be custom and retractable.

The problems:
1: The shocks on the rear landing gear don't seem to be strong enough for supporting the weight of the plane. I found some modded shocks to help the problem, but the gear still seems a bit weak.
2: On the real bomber, the rear landing gear folds up into fairings built into the back of the wing. My landing gear just snaps and breaks when I try to retract it into the fuselages I've designed to keep it in.
3: When I land the plane, it swerves and spins across the runway, despite how gentle I am with the controls.
4: The wheel on the front landing gear does not go into the fuselage when I retract the gear.
5: I'm currently using the landing gear without custom wheels, because the custom wheels were not small enough for the design I needed. These wheels are okay, but I'd be great if you could point me in the direction of custom wheels that are about 0.5u in diameter.

I know this was a long list of problems, but if you could offer some advice in any of these areas, I'd greatly appreciate it.