Using a more advanced counting system is not going to increase your EV by much. If it did, everyone would be using the Thorp Ultimate system (-9, 5, 6, 8, 11, 6, 4, 0, -3, -7). In fact, even level-3 system like UAPC are not worth the effort when compared to similar level-2 systems. And any system that requires an ace side count (like Hi-Opt and Advanced Omega) are not worth the trouble.
You should aspire to playing a simple system incredibly well. The biggest gains will come from playing faster (while still being accurate) and supplemental techniques (coupons, scavenger BJ, tracking, sequencing, etc.). The more comfortable you are with your system, the easier it will be to add other AP techniques.
-Sonny-