Here is my opinion speaking in generalities:
General information:
Between 1966 and 1988 Martin used Rosewood bridge plates which were inferior to the Maple bridge plates used before and after. I would not buy a Martin guitar unseen from that period and likely not at all.

In the matter of scalloped braces the highly revered late-1938 to late-1944 guitars had deeper scalloped braces than the 1938 and prior forward or advanced braced guitars. This gives the late 1938 to late 1944 Martin guitars improved bass response and are highly prized. Scalloped bracing is a big deal. Gallaher calls this voiced bracing and it matters.

I presume you're primarily a flat picker or you'd be interested in a 000 or OM sized guitar as a finger picker. Given that, consider that a D18V has a Mahogany back and scalloped braces and may be clearer in tone than a rosewood guitar. If you're a singer songwriter and play few leads the rosewood maybe ideal. Now the bluegrass master players revere the rosewood D28 , they'll say it is incisive and yet mellow.

Now since 70 t0 80% of the sound comes from the Sitka spruce top on the 18s, 28s, and 35s (scholars differ)you may think the 3 piece back makes little difference, but in fact, in general I think the 35 is less clear and defined that the 28s and 18s. There's a reason why most guitars have two piece backs, in general it just works best.

best of luck,
Chance