Larger lenght to beam ratio vs weight

I've been part of a fishery that limits boat length to 32 feet, beam weigh and height being the only variables often changed. I've fished on Wegly boats from 11.5 to the new 14 wide jumbos, and spent extensive time aboard (as much as 5 months a year) aboard a 13.6 ft wide curry and then a 15 wide curry the next year. I've also owned 32 foot boats from 12 to 16 feet wide ranging in weights rather substantially. Your splitting hairs asking ride perception on boats minimall dissimilar. I'll always pick the heavier wide boat but have found it takes a bit more that the given differences to make wildly different ride qualities. There were 3 distinct model wegley boats all a bit wider as time progressed. I'd you didn't skip models the only change was dinette width. If you jumped to the 14 wide from a 10 wide it was noticeable but the 10.5 to 12 wide rode the same except the 12 had room inside for a head and they packed 4k more pounds.... in 8 footers both bobbed like a cork.

 

The OPs first post says round bottomed, single engine, semi displacement hulls, which would describe a vessel not likely to achieve plane, especially in bad weather, so we’re talking about slow.
If the lines, power and loading of the two boats are similar, the difference in creature comfort aboard in the same sea conditions will be very slight, with a slight nod going to the larger hull, if indeed the difference is discernible at all.

 

Be very careful here not to confuse "large" with "heavy". A vessels motion in a seaway has three major attributes; its mass, its waterplane, and the encounter frequency. If the waterplane is too large compared to its mass, it becomes a wave follower and you get high accelerations and large motions. If the waterplane is too small compared to its mass, the vessels does not rise to the waves and is very wet. For each seaway there is an optimum length, beam, and waterplane depending on course and speed, this has to do with the harmonic between the waterplane "spring" and mass interacting with the encounter frequency. It is possible to "tune" the response based upon controlling the encounter frequency by adjusting the speed and direction of the vessel. This has more to do with seamanship than the overall waterplane and mass, but a poor selection of waterplane and mass makes for poor seakeeping in the expected seaway. This was very common to see when antipodean Farr broad stern designs came up to the SF Bay area. In some conditions they excelled, in other conditions they sucked.