i was just out shooting, home for the Holiday, I shot an old bear, my wife's Darton Valiant with the lowered grip, her NAT, and one of my own longbows. I tried floating the recurves out on the thumb pad, not for me, the NAT just falls deep in the hand with no thought, tight or loose the grip made no difference to the tennis ball sized groups I was getting with it. When I went to my straight gripped Hill style 'get a hold of it' seems like the only and easiest way to shoot that bow. Tight or soft grips on my straight grip Hill style bows don't seem to make all that much difference, but I tend to hold them tight enough so they don't move in my hand on release. I like a bow that I can just grab and still kill the deer, or small game.
The only grip that was not changed in all of our bows to fit the person is the NAT. Francis did that when he built it. On the Darton, my wife complained about how the bow would not sit still. I lowered the grip, trimmed the far side so it would fit into her hand without her thinking about, and used a satin finish.
The result was five straight years of filling deer tags without a miss, hunting from a stool on the ground with out a blind.
For me, what happened with my target bows and what goes on in my head when I am shooting game requires two separate approaches. I don't want to think about anything except where the arrow needs to go on game, getting the grip just right for my hand is an important part of that.