it's all personal preference. Personally, I set it to about medium tightness. meaning if someone leans on the game, and gets momentum going, it won't tilt out on them but will give warnings from fairly good nudge. and if the machine moves you most likely will tilt out.

Bowen uses a tech of jarring the machine one direction and counter acts that by quickly moving the opposite direction, eliminating the rocking motion. it's a train tech that must be practiced to avoid tilting out.

Would love to learn that technique! Has to be very precise I would imagine.

Put the game in switch test mode and shake the machine to you liking until the switch registers.

Start at half way up the bob, then lower if it's too tight. There is no 'official setting' for tilts.

Before making any adjustments, make sure the bob is centered in the circle. They often aren't. Remove the balls and raise the playfield all the way so you can look directly down on it. Loosen screws or slightly bend the ring or the bracket that holds the bob if needed to get it properly centered. An off center tilt bob is the worst. Because the bobs are shipped in the coin box (not installed at the factory), I doubt if Stern checks the centering in QA.

Anyone who owns a Stern that hasn't checked this should probably do so. They're often at least slightly off. Same goes for pretty much any manufacturer. I've also found them off on WMS games and one OZ. If you nudge, make sure you're centered.

We have most Sterns at BumperNets set with about 1/4 to 3/8 inch of the bob above the circle. + 1 to the comment about centering the weight. This is essential!

I usually leave a 3/16" gap between the ring and bob.

I use the Nimblepin method. If it doesn't tilt while he's over, I adjust it higher.

there are ways to nudge, slap without tilt even on tight tilts that will amaze you.
it pends where you hit the machine, if its an em, ss, dmd, wide body, etc.
if you watch zach sharpe or keith elwin, you will understand.
you play the game, it titls if you nudge once.
they play the same gaem and they man handle it without tilting.
its all about physics, length of "nudge" pressure, intensity.
slamming down on lockbar produces big nudge/bump with small movement of plumb bob for example.
buy pinball 101 dvd , you can learn plenty.

I played a new a new WOZ a couple of weeks ago that i tilted 3 times on, and i never tilt!

Took a look at the tilt bob and sure enough, it wasn't centered.

Check that mech!