I have a 24' Class C {E-350} and I've been using the same set of yellow Leggo blocks that I got at CW for five years. They are a little scuffed up from being pushed across asphalt a couple of times but not once have they shown any signs of breaking. Not sure how folks get them to break? :h
I've never had to go more than two blocks high and I always support both rear {dually} tires on the side that is being lifted. Only need a block or two on the front wheels about ten percent of the time. I have a level at the rear corner on the passenger side and a nother just around the corner on the rear so I can see both without having to move. Also have a small 4 way bubble level that resides on the dash.
It never takes more than a couple of minutes to get the coach level but then I've never taken more than 5 minutes at the dump station... just get out and git er done. It's just not that hard...
:B