I'm thinking I know the answer, but...

[Monkey Run]

Due to the extensive amount of work I plan to accomplish under my coach this winter, I'm considering placing wood blocks under the leveling pads when the air bags are full and then dumping the air to rest the coach body upon the blocks. Given that the HWH leveling system supports the body when in use, I would assume it's designed to sustain the weight I intend to place on the pads for a couple of months, thus avoiding constant starting of the engine to inflate the bags.

My storage building has a concrete floor, the blocks are 6x6 lumber.

[ThePowells]

Don, Absolutely.

Another thought if you are going to do that much work, you may want to consider pulling the coach up on blocks to raise the coach height and then add the same amount to the support blocks. This may make it a little easier to complete your tasks.
One last thought, you may want to measure the distance between the jack pads and floor. You may have a little variation between them and thus you coach will not sit level if that is a consideration for your planned projects.

[barmcd]

That's the way I do it using 12X12 blocks made of 3/8" plywood laminated to 6" high. I also found out that the coach doesn't always go back exactly where it started. The back jacks weren't a problem, but I didn't leave enough room under my one front jack and when I aired up the suspension, it didn't go up high enough for me to get the blocks out. I'd left less than 1/8" and it wasn't enough.

[Domo]

Levelers and air bags are variables.

Wood ramps under tires are fixed and reproducible.

[Monkey Run]

Hmm good thoughts, I'll consider them. Some of my work will be expedited with the body lifted, so at least in part, I need it lifted in that fashion. Otherwise and including the front HWH spring replacement it may be better lifted via the ramps.