As far as position goes the important part is the relationship of the wheel to the center of gravity is the important part. The axle of the wheel should be just in front of the center of gravity. Too far forward leads to poor handling. Too for back leads to nose overs. Lots of planes mount the gear blocks to the front of the wing spar. You can also rake the gear forward if you have trouble with nose overs. A tiny bit of toe in, one or two degrees, can help with ground handling. You may also need a little more weight in the nose to off set removing the weight of the nose gear and preserve the balance.