I am going to have my tandem trailer tires balances before winter to try and smooth out some vibration and after going to all that I would like to block my trailer for the winter to keep the tires off the ground. I have read the best jack points are right at the axle near the tires but should I block the trailer on the axle or the frame? My frame is U channel and I am concerned that it might bend from the weight. I also read conflicting information about letting the leaf springs hang vs keeping them compressed over winter. I have a 20' deck boat and my total weight is around 3500lbs.