Finding myself in the exact same situation, but with very little experience, thank you for showing how this can be done. I guess I'll just sneak up on it slowly and keep testing. Thank you so much for sharing. =)
Thanks! I was making a Piano Stand and absolute stability (and a cheap price) were paramount; off-the-shelf stands were either $120 or have a tendency to collapse. I was considering this as an option but I had thought I would need a jig or something. Thank you for showing me how easy it was!
Make sure your floor that you're leveling it off to is also level. Garages tend to have a small grade (1% or so) for water drainage. You can then put things under the legs until it no longer rocks, I recommend cardboard. The height of whatever you had to add to the short leg is now what you then have to remove from the longer legs. Conversely if you didn't want to cut, you could glue a rectangular slab of wood to the short ends. Mix wood glue with sawdust and you wouldn't even tell any adjustments were made.
Using a speed square with the circular saw will keep you from getting crooked cuts. When I shave off one leg, I always start by measuring the distance from the ground and the bottom of one of the "off the ground" legs. That usually gets me within 1/8" of where I need to be
