I spent several years in a 12x56 mobile home moving with the construction camps. We moved as often as 4-5 times a year and my job was the set-up. The short answer is use the screw jacks to get it all level during set up but then use cinder blocks as the permanent supports. The Cinder blocks can be painted, stuccoed, or closed in with skirting for a finished look.
I would level the trailer side to side, then front to rear, without any supports just the wheels and front jack. Then lower the front until I had 2 inches above level in the far rear. Then put supports just behind the wheels and raise the front back to level. Then just add supports (we used 6 screw jacks per side) after it was all level.
You need a good base for your supports. For your application driveway pavers should do. Make sure the ground where your supports are is well packed and has some protection from run off washing away the material. Maybe a perforated drain pipe for your purposes buried in gravel.
