Quoted from r0ddan:
This is written partly with the help of google translate. English is a second language.
I've been lying on my back under this game countless times screwing on the leg screws. all to find the right slope. I have read a lot in this thread to find clues to how to best solve, among other things, the problem with the inner loop sending the balls straight down the middle. This week I'm lying there again and now I was aiming to get 6.5 roughly in the middle of the playfield. I think I've finally found the right slope. Or I just got a little better at playing all of a sudden. One thing I have a hard time understanding. Why do I get different gradients depending on where I measure? high up and far down on the playing field can differ several tenths. And where should I get 6.5?
You will always get slightly different readings in different places around the playfield. I try to average it out, but for slope go mostly by the middle of the playfield. For level (left and right) I do the same, but mostly concentrate on the area closest to the flippers. While there will be some difference, it should be very minor and not make a huge change in play. Slight warp in the wood, slightly uneven clearcoat, and slightly raised inserts can all contribute to the difference you are seeing, but unless it's a huge difference, I wouldn't worry too much about it.
After leveling and getting the slope right, you still might have to adjust the lane guides on the loop and the orbits, and also the Tatooine scoop. Make sure the guides are tightened down well too...mine were a bit loose from the factory making the shots inconsistent. Also make sure none of the targets are leaning far enough to interfere with the ball travel, and check the roll-under switch gate at the Death Star entrance and the left spinner to make sure they are not affecting the ball. My machine needed a TON of tweaking, most of any game I have had other than Avengers. It's worth it though...once it's dialed in it is a super fun machine and it has needed very little additional tweaking once it was done. Good luck!