If you cut any shaft down an inch, it will drastically throw off the swing weight. If you haven't noticed that, then you likely won't have a problem with it.

Club builders can add butt weights or heavier grips to counter balance the the club head. Just let your club builder know what swing weight you want your club at and they can adjust what they need to get it there. If they have no clue what your talking about, go find someone else.

Shortening the shaft will make the club shorter but it will also make the shaft stiffer and adjust the swing weight as well. Plus, the more length you remove, the less flex your club will have. Depending on how much you cut it down, it could move a regular flex to a stiff or a stiff to an extra stiff. For every 1/2 inch cut, you will reduce sw by 2-3. Depending on your preference, you may have to add weight to the clubhead. For every 2 grams added to the club head, you add 1 sw point. I would suggest talking to a certified builder before cutting the shaft.