Nice project... For your front spindle mounts, did you give any consideration to the caster angle or are the pivot bolts 90 degrees to the ground? One thought, since the is a reverse trike, you might want to put some "positive" caster where the top of the pivot bolts would lean forward. This would allow the trike to lean into the turns slightly. Too much positive caster may cause some wobble, but probably not since the top speed is not too fast. 4 wheel live axle karts need negative caster to lift the inside wheel when turning acting like a poor mans diff.