Far out! I just began working on a simulation of the Verse in Universe Sandbox as well, using the same sources (The Verse In Numbers PDF and the official map from QMX). My intent is to create all of the star systems for the Orbiter simulation.
I'm using US to determine what a stable configuration would be, and then I'll use the resulting parameters to define all of the systems in Orbiter (free space flight simulator, seamless ground/atmo/space flight). For anyone who's a fan of Firefly/the Verse, and doesn't already know, there's a Firefly vessel for Orbiter with working shuttles, cargo bay and hover mule. All it needs is an Orbiter Verse to fly in, but this is a big project. I've started generating planet, gas giant and moon textures, but there's so many, this will probably be what takes the most time.
The one drawback in Orbiter right now is that the software does not support more than one star light source in a system, with regard to simulating a star's light. Inter-stellar travel can be simulated by using a plugin called MSSS that essentially just loads a new scenario for each star, once a vessel reaches a certain distance or coordinate field (defined in a config). I expect that multiple star light sources will be supported sometime in the future, once the developer or someone in the community codes it up, but can't say when.
Anyway, thanks for posting this up! I'll definitely check out what you've done and will most likely use it as the basis for what I'm doing. Since the 'artificial' stars in the system are 'compressed' brown dwarfs, I agree that they should be as low mass as possible, things appear too tight as they are for the orbits to be sustainable. I'm going to attempt to get something as close as possible to the official source (haha) and as complete as possible. It will be some months before I post anything about the Orbiter release, but I will certainly post anything that I do in US up here.
Cheers!