I have a few thoughts. Are you sailing with the main cleated off most of the time? I do. I've been practicing it for a long time, I'm old, and don't capsize all that frequently, YMMV. I frequently sheet in with both hands (like mad) when racing and then cleat off the sail and make minor adjustments as the wind changes. You have to spend some time setting the angle of the jammer so that a pull slightly up cleats it off and a pull slightly downwards pops it out. And practice that downward flip with the sheet tight for those OMG~!! moments.
I switched to the Harken system to get the ratchet. 57m ratchet fiddle with jammer and becket at the bottom. I got the 57mm double for the top because I really like Harken stuff, but it's not required. I think the Harken jammer with ball bearings in the cams jams easier too.
I don't sail in 30 mph winds, as I said I'm old, but it was 20 to 30 on Saturday and I sailed four races. Upwind the the main was tight, tight, tight, nowhere near the shrouds, probably as pulled so hard it only had about 8 inches of draft at the bottom. The shrouds would be about 30" away from the sail.
I was tired on Sunday but nothing hurt too much.
Hiking now, there's where you need to go to the gym.