My recommendation is to:
1. Download RAT (Random Assortment of Things)
2. Download Adjusted Sector
3. Install and Enable RAT
4. Configure RAT with the extra systems you want and nebula density
5. Edit starsector config
6. Change the map size in the starsector config to one of the sizes that works
Question. What's the performance impact of increasing the map? If I wanted to double the size how bad would the performance degradation be?
Quite high.
Aspect ratio for width/height is 41/26
205000 x 130000 = 1.25x larger
246000 x 156000 = 1.5x larger
328000 x 208000 = 2x larger
I avoided anything higher than 1.5 myself.
7. Open the data/campaign/terrain folder in Adjusted Sector's mod folders and copy-replace the nebula map size that fits the new sector size you chose, replacing the original map in data/campaign/terrain of starsector proper and renaming with the original maps' name ("jyperspace_map" or something like that)
This SHOULD keep all the new stuff in 0.96, but also let you have 250% more systems and a 1.5x larger map for example.