If someone would grab some of the more complicated ships from the second link (I am think the Falcon, a Tie Fighter, and the Starseeker personal shuttle are probably representative of the highest poly count you would want.) and convert them back to OBJ format. (I have no way to get read the format they are currently in.) I can figure out a good max poly count for ships. Since we are dealing with obj format, then that means that bump maps probably work, transparency and displacements won't.
BTW a 20 Poly Type S doesn't look that good, but at least is recognizable.
There is no way to do a Free Trader or Far Trader, or heaven forbid a Broadsword and even get close under those restrictions. The problem is Traveller ships, especially as time went on, have lots of rounded edges. When you have curves, especially 3D curves Poly Counts go through the roof. As an example, a good looking cylinder has 18-24 polygons excluding the ends, though you can probably in low res situation, get away with 12. For a Sphere you can probably get away with around 200 but a good looking sphere is around 400.
So a Ship's Boat is going to be at least 172 polys and to look decent should be more than twice that. A Broadsword is going to run you almost 500 Polygons without the cutter wells (or cutters sticking out). Adding the cutters takes you, if you are careful, to around 1000. (Without any turrets.) Double that if you actually want to have a decent look at it and minimum quadruple it if you want to look good at mid ranges. My guess would be that Andrew's (From his mini movie, "Striker") run in the 25K range at a minimum.
Which is why I am trying to nail down the reasonable specs for what the software is capable of handling.
I could also use a scale they should be done to. (I know they can be scaled later, but if everything is to the same scale it is easier.)
After all you don't really want an AHL to appear to be the same size as a Cutter.