When using loose Pyrex or Triple 7, how much pressure do you put on the powder when loading your bullet on top of the powder.

That is a hard question to answer. I load more by position on the ramrod then by pressure. I load on a clean barrel what I feel is an acceptable force for the seating. I do not lean on the projectile but move it down the barrel in a steady motion until the powder charge stops me. I then using masking tape mark on the ramrod where the muzzle of the barrel is in relation to the charge. I can write on the masking tape also, ie; 240/90g. Then when loading that projectile I know that if I take the tape to the muzzle of the barrel each time, the pressure should be about the same. If I find I can not reach that mark then a more intense swabbing of the barrel is in order. I have a friend the uses a fish scale to set his rod. That's all fine and good but too much monkey business for my liking. I haul enough stuff out to the range without bringing along the fishing gear too.

Till hear the powder crunch which is basically as hard as I can until the powder is compressed...to me, loading consistency is more important than any particular seating pressure itself

At least 40 pounds to seat the bullet on Pyrodex. less is needed for BP.....