There are a lot of really nice boats for sale and I wanted some perspectives on whether to look at fiberglass or steel hulls. I don’t know anything about steel hulls and currently I have a 34 ft Wellcraft 3200 Martinique. Also looking at having a twin diesels with 2 staterooms at least 40ft long. Looking at purchasing possibly next summer and my budget would be $60,000 or less. I am not afraid of an older boat and I also do like the classiness of older boats in general. The Hatteras, ChrisCraft, Grand Banks and older Trawlers I think are some of the nicest boats out there. Also, can I get roominess from a Trawler less than 40ft in length. Don’t want to be crowded with 4-6 adults if cruising the Great Lakes.
Hull material -- fiberglass, steel, aluminum, wood -- can be one part of the question, and then hull form (or shape) -- full displacement, semi-displacement/semi-planing, planing is maybe part two. That said... I'd expect much of that will fall into place as you research boats that have other features you need/want, at a price you like.
For example, 6 adults for cruising (more than just an overnight here or there) can be a first filter. From what I've seen, many 40-45' boats are often set up with two staterooms, one head or two, with maybe some additional sleeping facility on a pull-out or jackknife couch in the saloon, or maybe in a convertible dinette. Even that depends on boat style; an aft-cabin motor yacht or a trunk-cabin trawler (etc.) even maybe 35', may have that with two heads, whereas a sportfish or "Euro" model trawler at 42-44' may not (I think likely wont') have a second head.
Then maybe at the 46-48' mark or larger, you start seeing a 3rd stateroom, 2nd head.
All that very much a generalization, though.
(Ours is a 2-stateroom, one head model and it initially HAD a pull-out couch. Six on board for even one night would be a major pain in the a$$. YMMV, but our couch has been replaced with recliners.)
Maybe you can rummage through yachtworld.com and ID boats that appeal to you AND have three staterooms (if you think that's a good goal) and then use what you learn from that to focus a bit. (Maybe use something like the Hatteras LRCs as a benchmark for that style, maybe some other brands/models that appeal to you for trawler or ACMY/CPMY styles, etc.)
And what you see may make the hull material question sorta beside the point.
-Chris