I just received a personal message with respect to this posting about the importance of side to side balance. It's easy to check side to side balance in your drive way. Here's my method that you may already know.
I check side to side weigth balance by measureing the tire patch length on the trailer.
are on top of 2x6's and the trailer is level and loaded. Both tires
are at 47 pounds pressure though any tire pressure would work where both tires
are the same.
I take a two pieces of stiff paper and push one under the front of the tire and the other under the rear. Make sure the papers are square to each other. Measure the distance between them.
If they are equal or near equal on each side the trailer is weight
balanced from side to side. Typically if they are with in a 1/4 inch they are very good.
On my Scamp
16 the tire patch lengths are within an 1/8th of an inch, 6 1/2 and 6 5/8 inches which suggests they are well within 47 lbs from side to side. The contact width of the tire is 4".
I'm lucky. I've made no conscious effort to balance from side to side.