Sounds to me like a classic case of not having enough sail out. With the  
boom in the lower position, I would have left all the main out and furled the  
genny to 100% and brought the sheets inside the stays.
Using the main and the furled genny, I think you would have sufficient  power 
forward to do anything you want. Make sure that whatever ballast (people)  
are on board, they should become rail meat and have everyone on the rail. Yes,  
the gusts are a pain, but if you sail close to the wind with enough forward  
thrust, the big gusts can be dealt with by simply  loosening the main and  
dumping wind. I sail in this kind of wind all the time single handed. It's a  pain 
at times, but it does keep you on your toes and you will become a better  
sailor for it. The way I deal with it: I drink a lot of rum and yell a  lot.
 
Rummy.....had a great day of sailing.