Random thoughts...

500 lbs is up there on a Hobie 16, but going to weather, you should not be stuffing a bow if sitting aft.

Try traveling out a bit. You want to be sheeted tight.

Gusts can cause issues still if you sheet out... the sail gets full and can drive the bows down.

Main should sheet right to the deck, so if there is line between the blocks... you can rake further aft.