Welcome.
Definitely consider stretching it. My widebody is 23'6" with a 5'9" long pilot house floor and it would be pretty tight as a live aboard. With 2 forward facing helm seats I have about 36" from the back of the helm seat to the rear bulkhead with roughly 8' from the bulkhead to to the transom giving about 6' of usable deck for fishing. We plan on spending a week+ at a time on it with 2 people and an 80 pound dog, it will be very tight. It's basically camping in a boat and we'll either cook outside or eat out if we are in port. Fish deck wise it will be tight with 4 people jigging for bottom fish though doable. There's not that much room in a Tolman for things like a dinette, stand up head with shower, and a galley though the Jumbo does have the most room for those amenities.
Great Alaskans are built similar to Tolmans and 6" or 18" wider depending on model. The extra room is nice and they will support the weight of the systems a live aboard needs better while still offering good economy.
My wife and I picked out which helm seats we were going to use and did a bunch of layout with masking tape on the living room floor to figure out what would work prior to actually building.
