If you know the boat was a given length, which you may be able to deduce by comparing your plan with online photos. If you have the name of the model, you can often find out what boat it was based on, and that will give you the size of the original.
Once you know the size of the original, and the size of model, you can work out the scale. After that you can work out the height of the figures you will need for crew. Bear in mind that people were smaller back then, compared to today. The average height of an English male was 5'5" in the 17th and 18th centuries. I would not expect Americans to be very much different at that period of history.
If it was a Grand Banks Schooner, it could easily sailed out of Gloucester Massachusetts. There is a maritime museum in Gloucester that may well be able to help you with your enquiry as to the inner plans of the boats. I also did a quick Google image search of ‘Grand Banks Schooner plans’, and a couple of images showing inner layouts did come up.
From what I have read in the past, I got the impression that they did not use nets. The main attraction of using schooners is that they were fast, and a boat could get out to the Grand Banks, fish, and get back quickly with the catch and get straight out again.
The schooners would carry a number of dory boats, perhaps up to 12. Grand Banks dorys were simple flat bottomed boats that could be stacked on deck for transport (lots of plans online). The seats would then be dropped in and the boat lowered into the water with usually one fisher man, some food and long lines. The dorys would be left out for up to 3 days, before the schooner returned to pick up the fishermen and their catches. Then the schooners would race home.
I would imagine that as much room as possible would be given to hold space, and very little room for creature comforts, like bunks.
If you look on line there are many photos, and documents related to the life of Grand Banks Schooners, especially those out of Gloucester, Massachusetts. Here is a link that may help, the drawings are from the Library of Congress
http://www.themodelshipwright.com/prototype-shipbuilding/the-hull-the-heart-of-a-ship/.