You could certainly gap shoot with split finger but, the bigger question is, why would you? Your gap would be measured in feet instead of inches. This would be easily 3' if not 4' or more. So unless this is strictly a target rig, you're at a certain disadvantage against 3-under gaps. You may also require a different nock set for split vs 3-under so going back and forth, at least for hunting, would be more difficult as well.
Ideally, for gap shooting, you want to always have the point of your arrow somewhere on or very close to your target. If you're aiming a few feet in front of your target, especially at unmarked yardage with hills, obstructions, ravines, etc., you're setting yourself up for more of a challenge than you need.