My driveway slopes down, so when I need to level the TT, the first thing I do is chock the wheels. I extend the tongue jack all the way.
Next I lower the stabilizers onto wooden blocks. Then I let the TT set on the stabilizers and raise the tongue jack and set wooden blocks under the tongue jack. I repeat the process adding blocks to the stabilizers and tongue jack until the front of the TT is level. In my case I actually end up with a concrete block under the tongue jack.
My drive is steep enough so I have to watch the drain pipes in the back.
I was told 3 degrees is close enough to level. I do not know to measure that, so I do the best I can.