I've done so multiple times unassisted.
YES, one must be careful.
I position a bottle jack within reach on the side that I am working such that I can reach both valve and handle while handling the wheel/tire assembly. I usually position the jack beneath the nearest side of the swinging drawbar bracket but other suitable places exist.
The transmission must be in neutral and the brakes must be loose enough such that you can turn the brake drum with one hand.
Position the wheel tire assembly in approximate position such that it can be wiggled to final horizontal position. No need to index the wheel tire, simply rotate the brake drum. Use the bottle jack to fine adjust height.
Yes, you must be careful.
Not sure of the weight system that you have but you may consider removing it.