We are finding that the balls seem to pick up too much speed and then they over-shoot the next lever, so they then fall down the board. Sometimes they will get to the end but the extra speed will cause them to hit the peg and jump to the wrong side at the end. By tipping the top back a little we slowed the flow rate, and that helped, but I will need to build a new “stand” to make that work. We were at 7,500 feet, but I don’t think that should have made that much of a difference!
Something that may be worth checking is whether the surface under the stand is level (with the board set up).
An easy way to tweak the stand is to put some junk mail under the front feet.
Balls being too fast when they hit the bottom is a known problem. Generally, you can fix it by positioning the final ramp to face uphill. If you’re having speed problems elsewhere, that may not be sufficient.
If balls are moving too fast - which another post utilises to do speed runs! - it can be because ramps are facing the same way, allowing g the balls to accelerate. If the ramps switch directions occasionally, it will keep them from traveling too quickly.
We had to tip the board back about 5 inches to get a nice slow roll, but then it has to be steep enough to flip the levers. The balls start skipping right at the top, after only a couple of falls, but I can’t remember if we tried to go back and forth. At the bottom we did finally figure out to send the balls ‘up ramp’ so they wouldn’t jump over to the other side when we didn’t want them to.