I got a craftsman digital level for sloping games. Love it. Would never rely on my phone for an accurate slope measurement when you can get one of these for pretty cheap. You can even set it to beep when it reaches a certain pitch, so you can adjust the legs underneath & listen for the beep to let you know you have it.
One thing I've learned too is to first make sure the back is level & also maybe jack up the levelers even higher than you think you'll need them. Then deal with the rest of the adjusting from the front which is much easier.

I do have 1 little issue I ran into on my SST which I need to tend to, which is apparently one of the front PF hooks sits lower than the other because for me to get the PF level the game ends up wobbling, so its a good deal off. Need to try to bend one of those hooks or take it off & put some washers under the screws & bracket to get it to sit down further. Not sure which is the better option.