Most wooden boats will actually weigh less than commercially manufactured boats. Because wood is structurally efficient, a boat built with it can be made quite light. The only real downside of wood is that since it is a natural material it is not necessarily consistent in its weight. And obviously different wood species will have different densities and result in finished products with different weights.
For standard strip built construction with 1/4" thick western red cedar strips with 6 ounce fiberglass inside and out, a good estimate will be 0.7 pound per square foot of surface area. In other words a boat like the Guillemot with a surface area of 47 square feet, this will give a bare hull weight of about 32 pounds. When you add seats, bulkheads, hatches and other out fitting the boat should weight about 35 to 40 pounds.
Stitch and glue construction will follow about the same formula. While plywood tends to be denser, the typical material is thinner so the same 0.7 lbs/ft2. estimate works well.
Your results may vary, but this should give you a target weight to shoot for. The most common reason for exceeding this target weight is being heavy handed as you apply the epoxy.