In the begining I did think that more heel = more speed. Till I learned a couple of hard lessons this spring getting hammered as wind speed increased and I was not prepared. Now I reef earlier

Am I correct to think that a boom vang will allow me a little more windspeed before having to reef?
Another question; When I am on a beat, sailing as close to the wind as I can, I bring the traveler all the way in to the windward side and tighten the mainsheet as much as I can. It seems that I lose speed but can sail closer to the wind. Also the jib luffs a little at this point no matter how much I try to bring it in. Am I gaining anything? Would it be better just to tack?
Thanks,