Weights are usually measured in oz. per sq. yard.

If I was to cover the whole boat in 6 oz., then I would purchase the 60 inch wide with yards being the same length of your boat. 17 ft boat equals 17 yards to buy and then lay it on an angle and cut back on a taper so that you then can use that piece for the deck and so on. Standard weave is the usual. If you were to use 4 oz. on the whole boat then standard weave usually comes in 50 inch wide. If you want heavier on the hull then maybe separate pieces of 38 inch wide for the 6 oz. and 24 inch wide if it will span the deck in 4 oz. For the tape, I usually cut my own from the 4 oz. full length scraps for the outside seam, but using it on the inside is more difficult as it will fray everywhere, Just buy enough factory tape for the inside seams but you don't need a full roll unless you plan on building a few more boats.

There are certainly other types of glass which have different "sizing" which is the treatment of the glass so that resin binds and tighter weaves, but you will have more difficulty getting a clear wetting out with tighter weaves without experience with the product.