I just acquired a CO2 laser and have some questions

Yes, although with proper alignment it should be minimal. Figuring out where your laser’s sweet spot lies is part of the learning process.

It should be written on a sticker on the tube, but my “60 W” OMTech has what looks like a 50 W tube with narly a hint of a maximum (or even recommended) current setting.

For a genuine 100 W tube, the table in that post suggests 28 mA.

Set up a manual pulse at 50% power, fire it into a cup of water, then read the meter after a second. Double that current and you’ll know what the power supply’s maximum current is set to. If that’s around 28 mA, then you’d want to keep the power below 70% for much of your cutting. If it’s grossly higher or lower, then there are likely other issues.

Quite the contrary: you may need to throttle that puppy down.

Cutting 6 mm plywood chugs along at 6 mm/s with about 40 W from my 60 W (claimed) tube.