That seems like a pretty high sensitivity.
I also use high sens: I grew up playing ut99 on a desk that had about 10 inches of space for the mouse, so I had to use high sensitivity to make up for it. Eventually it became muscle memory and til this day I'm a wrist player.
I'm at about 3.3 inches for a full 360 in-game. How many inches does it take for you to make a full 360?
Sidenote: You might do this already but I'll share the tip anyways for anyone reading: For sniping, if you take a look at my vids, a lot of the aiming is done with left/right strafing. I use my mouse to make sure it's on the right axis level, and then use left/right strafing to make the small adjustments.
Rarely will you see me moving left/right with my mouse to adjust for a hitscan shot, I rely heavily on strafing for that. Once I know my xhair is at the right level, I let strafing do most of the work.
Been a while since I played ut, hopefully I can catch a few games this weekend. Hope you guys are doing well, see you in the arena sometime