my grip article is meant to serve as a starting point for developing grip (lining up the joints, disc plane, and tendons). recently i've found (due to short fingers) i've had to make significant adjustment in regards to the seam in order to build stronger leverage on the disc.
This is all good information. The reason I am rethinking it all is because I got a sweet blood blister on my ring finger, and I realized it was because I wasn't putting enough downward pressure with my thumb, which caused the disc to slip and rotate on my ring finger. I just want to make sure I am using the best grip for my hand ultimately. I went and played in the field today, and just worked on using pressure with my thumb, and it did seem like I was getting a much better rip.
a control grip is generally going to be weaker than other grips. you are probably correct with what you have found with your thumb, but be careful that you don't start gravitating towards more of a pinch grip than something more powerful as this is often the case when focus on thumb pressure starts to dominate. if you have to break the seam in order to get more natural leverage, that's fine. as long as your wrist hinge lines up with the disc plane, there won't be any power loss due to OAT.
if you don't have enough thumb pressure you won't be able to get any leverage. if you put too much thumb pressure, you'll weaken your finger grip on the rim wall and lock up your forearm/wrist. in many cases getting your hand more "on top" of the disc alleviates the need for excessive thumb pressure. i tend to think of the thumb as more of a stabilizer, holding the disc into the fingers... if that makes any sense.
tape can also help to prevent blisters. i tape 3-5 spots on my hand every time i play.