With variable wind speeds and wanting to hold a particular heading and wind angle, set your pilot to TWA rather than AWA. That limits the course changes from different AWAs as the wind speed changes (assuming wind direction is relatively steady).
Regarding your original question, depower in the first instance by dropping the traveller, as mentioned earlier. Don’t ease the sheet as that makes the main fuller (ie more powerful). This is something you can learn on a Hobie 16.
But the better
advice is from Maxing Out to stay reefed to the gusts and use an engine to help when the wind drops. There’s no
rule against motoring, and it doesn’t make you less of a sailor. If you’re not
racing (or trying to outrun weather) be kind to your
gear by not over stressing it.
All that said, if an experienced crew were
racing your boat, I suspect they’d ignore the reefing guide and let the
hull fly. Of course, it would be a good idea to replace the standing
rigging after that
passage.