Straight 35,37,38 helix. OR 41/37 helix. Some are using bigger spreads also. Like 41/35, 42/33 etc. The straight 35 probably best ALL around for trail.
Pick you poison on weights. (Heavy hitters, Daltons) Dalton Black/orange secondary spring.
Lots of clutching set ups and different helixes/weights/springs being used. But many using some form of combination of the ones I listed.
Trail set up will depend if tuned, gearing and traction. Not sure how many are using the stock primary spring. Myself I do not. I like the Yamaha yellow/green/yellow OR yellow/white/yellow for primary. Its hard to say XYZ will be best(trail) as so many guys are on different components and set ups related to gearing, traction, tracks.