Re: the blocks - they fit together like this:
The instructions with mine indicated that you should not stack them more than 4 high. I used the whole bag of 10 for the photo. You can use one for 1 inch, 3 for 2 inches, 6 for 3 inches etc.
In larger RV's I carried plywood that would go under the stack of blocks to prevent them sinking into mud or grass.
Do you have dual rear wheels? I had rear duallies on my B+ and found it easier to use approx 20 inch lengths of 2x6 wood on the rear wheels.
No, I don't carry all those with me
All the levels shown basically indicate the same thing. My take is that 1 block under my left front wheel would have leveled my van.
My van was level enough to run my fridge without further leveling.
A bubble level (like the little square one) assists you a bit more in determining if only one wheel needs to be raised.