So I've been modeling ships and planning my own campaign for a while now, but I've run into the brick wall

of my inexperience with freespace 2's data structures at this point, and I really need to start playtesting at least a few of my models before I go any further. Here's the catch though:
Question 1:
I intend this campaign to NOT use any of the ship designs in the original Freespace 2, or anywhere else for that matter. I had hoped that in order to free up resources/minimize loading sequences, I could create my own ship.tbl (and other associated .tbl files as they were needed), and if I'm going to use such a design, I might a well implement it from model 1 onward rather than do a bunch of work and then find out my intended design was impossible.
Really what I'm asking is how I might create a fresh slate (without using a modular table file), and then start playtesting from there in FRED. I have a sneaking suspicion though that what is going to end up happening is that in order for me to do such a thing, I would need to create a whole other directory of FS2 and gut the ships.tbl file that comes with it. Is that correct or is there an easier way?
Question #2:
I can see all of blue-planet's excellent craftsmanship in the fred menu, but I'm really quite puzzled how they managed to convince fred to read their .tbm files when it seems that their naming conventions of their tables are non-standard. It's a roundabout way of saying it, but how does fred "find" and "see" which files are talking about ships? does it simply look through all of them at once and say, "Well, this XYZtable.tbm makes references to all things dealing with ships, so I should probably implement that in the ship menu," etc. If I can find this out it would really go a long way towards helping me implement my own material, which right now fred doesn't feel like acknowledging. More specifically, exactly What structures/files/tables absolutely need to present (in either a .tbm or .tbl I guess) before Fred finally says, "OH! A NEW SHIP! LET'S ADD IT TO THE LIST!"
I am very open to better ideas though that would save me time, money, and several bottles of Advil. I suppose I should also be asking if it really would be a less of a headache to simply use a .tbm, then disable all the ships in Fred that I don't want to appear in the campaign. My real concern at that point would be computer memory and engine resources, assuming that this mod grew to include four different factions worth of ships in addition to what's already present in the vanilla... would that be too much for it to handle? I haven't been able to find much in the wiki concerning that.
I realize that this request is highly unusual- most people are content to copy and paste into a currently existing .tbm file, and that it is likely that I am being over ambitious. Odds are this project will take me several years of on and off work, but in the mean time, I would deeply appreciate any technical help the community can provide me. So point me in the right direction, or kick me if that's what it takes. Thanks a ton!