Leveling

I found a really cheap seemingly bullet proof way. We live in horse country so our Tractor Supply had these in stock. I got a 6 foot by 4 foot horse stall mat. The thing is 3/4 inch thick and heavy as lead. It's made from recycled tires. I can cut them to fit for the dual rear wheels and make narrower pieces for the front wheels. There is diamond pattern on one side and diagonal grooves on the other. I can easily make enough stackable pads to get all four wheels 2 1/4 inches off the ground so given that I'd never need to do that I can for sure raise two wheels 3 inches or more. It was cheap too. I paid 39 bucks for the pad so if I need another, the bank won't break. Found some really nice heavy rubber chocks as well.

Now, does anyone have a rule of thumb about how close to off the ground is acceptable. I have been measuring and if the wheel well rises more than 2 inches in relation to the tire I'm stopping there. It makes sense to me that we will sit steadier the less weight we put on the leveling system and more weight on the tire.

I ask because we notice the washing machine shakes the MH pretty good on spin cycle. So I'm guessing that leaving more weight on the tires is better.

Thanks to all for the suggestions