I picked up some cheap levels from Amazon that worked better than the bigger, more expensive levels I had around.
I drove a screw into the front of the beam to hold the small ones when not in use (the bigger ones I show below have much stronger magnets, but the small ones are easier to use)
$7 ea https://www.amazon.com/gp/product/B06XNWXKWN/ref=ppx_yo_dt_b_asin_title_o03_s00
The small ones I show below are the $9 pair, and I think those are what I’m going to stick with. They have a button magnet in the center (not exposed on the bottom) and hold pretty well. If they fall off when in operation or moving around I may change my mind
The $2 ones have an exposed flexible magnet on the bottom, I don’t trust it (it’s also much smaller, so harder to read).
The $7 are handy, but not nearly as convenient as the $9 pair.