i like the old, skinny boards
and have some older FAT boards too
for your weight in 15 to 20 knot winds, i would suggest a little larger sail(s)
in 20 knots about 5.5 and in 15 knots about 7-oh
and perhaps get/use one in the middle - like 6-oh or 6.5
ideally you should NOT sail with a "bum shoulder"
at least wait until it hurts less

also, have you considered the EZ uphaul ?
it does NOT cost much more than a regular uphaul
yet it helps break the sail from the water using your body weight and harness
i use it when my 10-oh gets water in the luff = heavy and painful
Gute Besserung und Alles Gute !!!