switch from ao2 count to zen count for shoes?

Using the ao2 count I find it hard to keep a side count of aces on shoe games. Would results be better to switch to the zen count? Only difference is the ace is counted as -1 and 9 as 0 instead of reverse. If I do the switch for shoe games can I use the same ao2 index #s or do I need to learn a whole new set? Anyone know how these systems compare in value? example ao2 with ace count vs zen, or ao2 without ace count vs zen?