I would (and did) do the following..

Adjust the outlanes to their innermost position. They are still drain monsters but not nearly as bad as they are in their default positions.

The roll-overs almost certainly need to be tweaked to be just right. If they are too sensitive, they will be triggered by random vibrations. If the ball is in the shooter lane when that happens, it will auto-launch! So first make slap the game in switch test mode and make sure none are accidentally triggering. Then go through them and bend the leafs to be as sensitive as possible just shy of accidentally triggering. It makes the game a lot more fun when you actually get credit for every character rollover, not to mention TOTO.

Tweak the lock/release release mechanism on the right. If it's hanging too far down, it will keep balls from rolling all the way forward into the path of the optos that tell the game a ball is locked. If it's too far up, it will release multiple balls when it should only release one. Tuning this to be just right is a bit tricky. If you pull the playfield forward you can see a little metal tab that determines the height of the lock arm. Gently bend it with needle-nose pliers to tweak the height until it's good.

Adjust the spinning house/feet pop-out mech. There's an adjustment for this where you can change the house's position as well as the strength of the coil that pops the feet out. I've never been able to get mine perfect -- if I set it to the position where the feet come out all the way, the post that pushes them out binds up and can't retract, causing the whole house mech to freeze up until it's manually popped back into position. The closest I can get is the feet popping out at a bit of an angle. You might have more luck on your machine than I did. When I got mine they barely popped out at all, though, so adjusting it helped somewhat.

Order replacement flipper bats from BAA. One of mine broke after 3 weeks and I've heard of others breaking. The plastic seems more brittle than on traditional flippers and breaks apart where the bat meets the shaft. You might not have this problem in home use, but it's nice to have spares if it does happen. I was glad I did!

Software adjustments:

Turn on ball save.

Turn up the time you have to get back onto the twister playfield to start munchkin modes.

Set tilt warnings to 2 per ball, instead of the default of 2 per game.

Turn down the slingshot power -- at default they send the ball airborne and cause the slingshot arm to pop out from under the rubber. The same goes for the slingshot up by the OZ lanes, but I believe that has been turned down in the default settings of the latest software. If you turn it up to get more OZ lane bouncing action, the rubber up there -will- break and it's a pretty big pain to replace it. (People say having a white rubber fixes the problem, but mine was white and broke just the same.)

The game is still very hard at these settings. Nobody has even cracked the default GC score yet on my machine on location, and that includes multiple PAPA A division finalists who play there!