should i switch counts?

I've been playing for about 2 months. I studied blackjack for nearly a year without playing (!@#$ Iraq.) I mainly play 6 deck shoes DAS S17 I thought the Hi-Lo system would suffice. But I'm tired of having a descent count and losing with a hard 17 vs 18,19.

I was thinking of taking a break from playing and studying up on Wongs halves count b/c the 7 and 9 are counted. Would this make any difference? and what are your opinions?