Great vid Scott. Just to add to that, slight variation, the inc/dec volume commands can really be your friend here. I tend to do as Scott and balance through my amp level by ear using cans or whatever I happen to be using to get it in the ballpark. I then turn up to gig levels and use the inc/dec commands through my midi board to fine tune. Those commands adjust the overall output of the preset from the output mixer in 1db increments and saves them there automatically. If your midi board is capable of it, it saves you ever having to touch the AFX while your balancing levels. It's extremely quick. I have 2 IA's on page 3 of my LF Pro set for inc/dec which can be accessed with a 2sec hold from page 1. It took me all of 30 sec to set up once and is one of the biggest time savers ever for me in balancing levels. You simply click between presets from your midi board as you would at a gig and click inc/dec as needed to fine tune.
On a side note, Scott touched on it, but make sure you balance levels between drive/boost levels and unboosted (if boosts or drives are used within any effect blocks) within each preset before you go balancing levels between different presets. For solos, I use the same trick as a few others on here and have all my presets load with a master volume of CC111 and I have my boost trigger CC127. That means I engage my boost before I check levels to ensure there is no clipping. If I have an effect block (delay, drive, filter, whatever...) that has a boost of any kind programmed in, I make sure it is engaged with the boost as well just to make sure there is no clipping. Scott's unity step should keep you clear in most cases, but it's better to be safe than sorry. Clipping your AFX outputs is a truly horrible sound.
As for your tone cutting though a mix, that has much more to do with your EQ than your levels. If your guitar tone is stepping all over other instruments in the mix, no amount of boost is gonna make you cut through. The most it will do is make one big mess with you at the center of it. If your preset levels are even and your presets are built and EQ'd properly (wether through using the proper IRs or an actual EQ) a good mixer will always have you sitting nicely in the mix. If you control your lead boosts, the same will be true for your solos. In short, if your getting lost in the mix and you've followed Scott's process, it probably ain't the levels.
Sorry to Scott for hopping on his cloud. Hopefully that was helpful. All that is meant to be in addition to Scott's method, not in place of. Again, great post Scott. Always good to see other methods.
All IME, IMHO, YMMV...