Don't mean to hijack the thread, but I too have this concern.
I'd like to jack both wheels up at the same time to facilitate tire replacement, and read a lot of posts on this topic. One post suggested consulting the manual so I did. Here is what mine says:
Place a minimum 10 ton bottle jack only directly under the trailer frame near the flat tire on leaf spring axles and on the lip directly below the attachment point of the axle on torsion axles. Do not jack up at any other point. Serious chassis damage can occur if other jacking points are used.
:h
I think I have torsion axles but I really don't know - and therefore don't know what jacking point they are referring to.
A recent flat was changed out by the roadside assistance guy by jacking under the axle near the brake drum but that lifted the flat tire only. Trying to get some experience jacking this thing up for future reference. I'm sure if I hauled it to Discount Tire to get new Maxxis tires installed, that this is what they would do.
I don't have a bottle jack - but I do have a two ton floor jack.