Speaking from experience and preferring to build large-scale models I feel that this thread has only lightly touched on the unique problems associated with big model boats.
These problems are not just confined to planning or transport you also have to consider the problems of launching and storage of such a large size and therefore heavy model. Any model over 6ft in length is difficult to carry, manoeuvre and lower into the water and is better handled by two people.
A model over 8ft in length, being so cumbersome and loaded with ballast, is best launched from a trailer which of course would require that the boating lake has a slipway and that your transport is either a very large car / van in which you can fit both the boat and trailer or you fit a tow ball.
A model over 10ft long has to be treated like a full size boat and put on a trailer both for transport and launching.
Don’t forget that big models require a lot of storage space
Paul