I've run one or two computer tests of this idea some years ago.
The theory being tested was that one is likely winning as the high cards are coming out; so only wong out when the TC is <= -2 and one of two things happens: (1) you lose a hand; or (2) the count stops dropping.
This does NOT work. It is only trivially better than not wonging at all.
One piece of advice: uses a ROUNDED TC for wonging purposes even if you use a floored or trucated TC for betting and playing purposes. IOW, wong out @ a TC of -1.5 or lower.