Usually, the bow hanging up on the bow stop is a sign of backing in too deep causing the stern to rise and the bow to drop. Therefore, putting less boat in the water is the normal solution. Also a keel roller after the bunks and before the bow stop is another potential help for this type of situation. However, it looks like you have tried both of these with no luck.
Another thing I seen done to get around this issue is to let out a foot of strap off of the winch before backing in all the way, tap the brakes on the way down the ramp when the back of the boat hits the water and get the bow to slide back off the stop before getting to full launch depth. Not optimal I know, but if you just have to launch every once in a while if you keep your boat on a sling or only occasionally visit a steep ramp, this may get you by. Just be careful not leave the winch in free spool and only let out enough line to clear the stop.
Just curious, does this happen to you at the Sea Isle neighborhood ramp?