I don't balance tires on my trailers simply because trailer hubs aren't balanced and those 26" very short leaf springs work like a big damper.
My truck tire dealer many years ago showed me what happens when a tire is spun balanced then placed on the trailer and spun with a old spin the tire mounted to the vehicle machine.
1. he mounted a LT tire (no weights) on the jacked up trailer and spun it...no shaking.
2. then took the wheel off and spun balanced it per lug center adapter....placed it back on the trailer and spun it up...the trailer shook severally.
3. he then pulled the weights off the tire and spun balanced it on the trailer...matched marked the stem to one of the lugs. Just like #1 no shaking.
He then rotaded the wheel two lug holes and spun it up....more shaking.
Moral of my story is if I was going to have a tire balanced on any of my trailers it would be done on the trailer.
Rotating ?
Only if a brake loacked up and severally flat spotted one tire I rotate it with the spare.
Left and right turns scrub the tires differently so wear equals out.
Loads fore and aft....side to side change continually all making same wear on all the tires unlike the tires on the tow vehicle.
Other folks have their own ideas.