Checking twist is a reasonably easy task. All you need is a felt tip marker (I like a 'Sharpie'), a measuring stick or tape measure, and a cleaning rod and tight fitting patch. The cleaning rod needs to be one that the felt tip marker will mark on and you need to be able to see the marks you make. Can be difficult with a blk. coated rod. I use a "Dewey" brass rod or you could use an aluminum one. Either way , you'll need a rod with bearings (so the rod will rotate easily). You can use either a cleaning jag or a loop on the rod. Put an oversize patch on the rod, but not so tight you can't move it, but, it needs to be tight fitting to the bore. Trim a patch if need be. Push the rod w/ tight patch 8 or 10 inches into the bore. Now put a small mark on the top of the rod at the handle. Put another mark on top the rod at the rear bridge of the action. Push the rod further down the barrel watching the mark you made at the handle. When the mark at the handle has made a complete revolution, stop and make another mark at the rear bridge. Remove the rod w/ tight fitting patch. Measure between the marks that were made at the rear bridge. This distance is the twist rate. ( If the rod traveled 10" before the mark at the handle was back in the starting position, your twist rate would be 1 in 10 inches.) You could use a coated rod that is undersize (say, a .22 cal rod) if you applied masking tap so you could put marks on it.
I've never had too much trouble with Jewel Triggers and H-S stocks. If there is any problem it will be on the 'safety side' of the trigger. If you are uneasy about hacking on a $300+ stock find a pro. Not everything is 'drop it'.