This is good info.

Now, suppose the crew weight combined was more like 150lbs for myself and 120lbs for my girlfriend.

Would I be able to avoid double trapping if I were to sheet out?

The reason that I ask, is that my girlfriend is deathly affraid of sailing and I don't think I will ever be able to convince her to get out on the wire.

I honestly don't forsee myself sailing on more than 10-12 knot winds.