I’m 15 stone and my RP23 shock just does not perform, so I swopped it out for a Vanilla R Push’d for trail riding awesome,also balances out the bigger fork by keeping the rear up in the travel, where the RP23 drops through its travel.
ZTR Flows are a good compromise between weight and strength, 729’s are seriously heavy rims,
I would go 10 speed slx with the double and bash up front, has steel pedal inserts and is built a bit stronger than the triple, and a short cage rear mech.
I have the maxle back end which is super stiff, which my 08 Heckler wasn’t.
and the best mod is a dropper seat post.
And as said get an XT cassette as the SLX still eats the Alloy Pro II free hub, mine did.