Got some scrap pieces of 8 x 8 x 3/4" black HDPE at a plastics shop and bolted them to the bottom of the stab. jack feet. Used s/s nuts & bolts and countersunk the bolt heads with a forstner bit. Used a roundover bit on a router to make the rounded edges. Used to use plastic lego blocks - damaged 2 or 3 of them in a couple of years. Now these pads are always there and don't have to think about them - very strong and will outlast the trailer.
Lippert has 10" round bolt-on Elephant Foot pads.
With the BAL Lock Arms, there is substantially reduced movement and I don't find the need to build up layers of blocks or wood. Tried stacker jacks but the Lock Arms work pretty good and are faster and easier to set up.