what I was looking for was a good 'jumping off' point for my specific vehicle

The vehicle environment is going to be the smallest difference compared to the other factors in the audio chain. The speakers are going to be the biggest.

And before you say "I am using the factory speakers" keep in mind that most people replace the factory speakers so using one of their EQs is still not going to match your equipment. And then there's the fact that even if they did use the factory speakers, the amp is going to be different no matter what. Also different vehicles have different speaker and interior options.

I would guess that you probably wouldn't be able to find another empeg owner with the exact same car, interior, speakers, and amp as you have. Without all of those factors in place, there is no "baseline" or "jumping off point" at all.

If you're not prepared to LISTEN to the sound of your stereo and make your own judgements of where to make adjustments, then you have no business messing with the EQ. I'm sorry, there is just nothing that anyone else can do to short-cut the necessary process of LISTENING to the stereo and adjusting the EQ in that environment.

(Except RTA, which is mentioned in the FAQ entry I just created).

as opposed to the default 'flat' (which is not truly flat anyway)

You are quite wrong there. I have personally tested the output of the empeg with an RTA connected directly to its RCA jacks, and it's ruler-flat, flatter than any other commercial car CD player (most of which come "tweaked" a bit out-of-the-box).