57/63 gears
141 2.25 PClaw track
M A arms
helix and weight sounds good.
This.
I ran 3800 miles on an 11 Xfire at 9k & up in CO, First thing is arms... if you run wide arms with a short track, it will wash out badly. I'd actually look at the 36" M kit from alternative imapct, the narrower you go on a short track the less you lose traction on the front of the track in a sidehill.
The 2.25 PC is a great track, I'd rather have more paddle given the choice, I'd think about possibly going to a 146 CE 2.5 just for the lug, but you'll spend more on the track, and more making the 146 work on a 141.
Never ran that sled stock (boosted it new) so not helpful on clutching, but it looks like you're close. I'd think about doing the open helix if you're changing anyhow, that gives you ability to change spring/ add SA washer without removing helix, and lets you adjust secondary tension.
If by chance you can find the 144 CE 2.5 track... that would be a good choice as well. It's no longer made I don't think, but worth taking a look for.
If you really wanted a sweet setup though... the new 2.6 from the 2016 is hard to beat. Best track in that length range by far.