most shafts are going to vary a lot as the wood density varies from piece to piece. a custom maker can pick out a piece for you if a specific weight request is made. from production, you'll either need to go and weigh some stock if you have access to a store, or find a retailer that is willing to weigh some for you. i have found that the OB shafts are pretty consistent in weight, I believe due to the way they are constructed with many thin veneers, which reduce the overall variance. mezz shafts are also very consistent, around 4-4.3 oz, as they are very careful in their wood selection. but all the rest you will find a pretty wide variation in shaft weight.