I purchased a used samick deermaster from another member here and when I measure the brace height from the string to the grip it's only 7".  Spec is 8.25 to 9.  I've twisted the string to get the brace height to 7.5 but it was darn near impossible to get the string on at that length.  Should I keep going or am I measuring it wrong?

Are you measuring to the deepest part of the grip?

If your measuring correctly, like stated above, you probably need a different string.  I had a Deermaster TD and it was a 60 inch AMO bow, I like to use a D-10 flemish string 3 1/2 inches shorter than AMO length for my recurves. If I remember right, I shot my Deermaster at about 8 inches bh.