Here's a too-tight cassette lockring removal tip, just in case. It'll save some knuckle skin, and keep a few $ out of the swear jar:
Get a big O/D washer with I/D that will just fit the skewer axle. You''re looking for a washer that's bigger than the cassette lockring tool. Lowe's has 'em. something like 15 cents ea.
Fit the cassette lockring removal tool into place, and then run the skewer through the hub. Place the washer on top of the lockring removal tool.
Adjust the skewer so there's just a few mm of slack.
Use an open end wrench on the lockring removal tool, while holding the cassette with the chainwhip.
The skewer and big washer should allow the lockring removal tool to turn (eventually... eat some spinach)
while preventing it from slipping out of the lockring.
Once you have the lockring loose, just remove the skewer and proceed to swap the cassette.