I would just use some scrap 2x6 or 2x8 boards about 18" long and use those..
I was setup and a new neighbor was setting up behind us. I heard this crunching and breaking sounds. I looked over and he was using those "Lego" type of stacking blocks and they were just crunching due to the weight of his Class C.
I had a couple of extra boards and offered him one. That's all he needed. I was leaving the morning, so I just said, keep it, as I'll be leaving in the morning, but no worries.. I got more at home.
🙂Anyway, I've been using the same set for almost 20 years and still working great.
That's just what works for me. I don't need them for leveling that much, but use them for the stabilizer jacks (I have a TT) but when I do need them under the tires, they work great!
Good luck! Mitch
2013 F150 XLT 4x4 SuperCab Max Tow Egoboost 3.73 gears #7700 GVWR #1920 payload. 2019 Rockwood Mini Lite 2511S.