Brandon,
This is a great question, thank you for taking the time to reach out. The more the top hand thumb is stretched out long the more difficult it will be to feel the pinch of strength we are looking for in the top hand. There is a sense of strength in the top hand based very much on the individual and specific hand size and strength. Make a fist in your top hand and allow it to hang naturally by your side. With your fist by your side, grip the club with strength. This should give you a sense of what to feel in the top hand. The bottom hand is gripping around not only the grip but the thumb of opposite hand as well. This hand will feel more in the fingers with the pad of the right hand resting comfortably with pressure down on the top thumb.
Notice the picture (link below) of Hogan’s grip and pay close attention to not only the bottom hand but also the “trigger finger.”
Hogan’s Grip
Thank you for taking the time to reach out, we hope you find this beneficial!