When I am trying a new bow, how much attention should I pay to weight?

Let me stress that above all else,  we are concerned with the kind of sound that comes from the you, your violin, and the bow  you will be playing. The best weight is that which sounds the best on your instrument. The best weight for a bow depends somewhat on the violin you have, and somewhat on the player. A bow weighing as little as 58 gm. can work well, but rarely over 63 gm is helpful. This overall weight can be strongly affected by the type of winding, the material  the frog is made from, and what kind of metal is used to mount the frog. Gold is substantially heavier than silver; a faux whalebone or  spun silk winding will weigh 2 or 3 gm. less than an ordinary silver wire winding. An ivory frog will weigh two or three gm. more than an ebony frog.

More important than weight, of  course is  the balance of the  bow, i.e., how heavy it feels in the hand. Depending on how the shaft is mounted, the finished weight can vary as much as 5 gms, yet the feeling  of balance will remain nearly the same. It is therefore, largely the weight of the shaft that gives the bow the balance which you experience; the shaft weight should be  between 35- 39 gm. The feeling of balance is best determined by what I call the  ‘head weight’. I use a system that accurately measures the head weight. For most players it is 16.5- 18 gm. More advanced players tend to like a heavier balance.

All that being said, the flexibility of the shaft may be even more important than the precise weight. To sum up, any bow that weighs between 58 to 63. gm. has the potential to optimize your performance. For a viola, 68 to 73 gm; for cello, 78 to 83gm.