That depends on your PAP coordinates. It should be quit strong no matter how you drill it because the cover is pretty strong.

You stated that when you have placed the pin under or on the bridge line that you have rolled over the thumb. I don't argue that fact but it is unusual because how close the track is to the thumb is a result of the release and should be unaffected by pin placement. I have heard of high track bowlers having trouble with flaring over the finger holes when the pin is under the fingers. This is a result of the pin placement affecting where the intersection of flare happens. Moving the pin up moves the bowtie up which gets the track a bit farther from the fingers, but doesn't affect how close it is to the thumb. The track that is closest to the thumb and furthest from the fingers is the release track and as the ball flares the track migrates away from the thumb and toward the fingers.
When you have had the pin under has the CG ended up below grip center or the ball ended up with thumb weight after drilling?
The reason I ask is that a bowlers release can have small changes due to static weights. For me when I have some finger weight after drilling, my track ends up slightly farther away from the thumb due to the fact that I am carrying slighly more weight on the fingers which allows my thumb to exit a bit quicker while I have a bit more axis tilt which lowers my track.
There are also some tricks that can be done with your grip that help to lower your track.
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STORM TRACK
 
formerly : Stormin1

If you get caught in the Storm Track beware it could be a Typhon or Monsoon with Rolling Thunder and Lightning Flashes that when Unleashed may send splintered Wood flying everywhere.