While we can adjust the boat we cannot adjust people. A berth is the same size on a 34 or a 48 but there are a few tricks. Before we go to that, lets consider some broad decisions. Most small yards have gone to travelifts and thaey accept 16 ft. for an 18 you need a larger lift. This limits your access to yards that handle bigger boats.
Dockage is another problem.
Most slips for a 35 footer are 12 ft some 14 ft. wide. Yep it costs a little more, but is better than that end of the pier spot. When I came up with the Coral Clipper 65, both of these factors played in the design and consideration of a monohull. Power is also a big factor. The Catfisher 34 had a pair of 50HP Pathfinder Diesels.