Well it is a bit hard because in most games the NPRs are hidden from the spacemaster, unchecking the box for this setting might make it easier to do what you're talking about.
Anyway I finally built a jump tender for my new game.
GildedStar class Jump Tender 10,000 tons 653 Crew 1757 BP TCS 200 TH 166.5 EM 0
1665 km/s JR 5-250 Armour 6-41 Shields 0-0 Sensors 1/1/0/0 Damage Control Rating 6 PPV 0
Maint Life 3.67 Years MSP 2659 AFR 133% IFR 1.9% 1YR 307 5YR 4602 Max Repair 702 MSP
Magazine 850
Jump Tending Drive R-10k Max Ship Size 10000 tons Distance 250k km Squadron Size 5
Ion Engine E5.95 Prototype (6) Power 55.5 Fuel Use 59.5% Signature 27.75 Armour 0 Exp 4%
Fuel Capacity 800,000 Litres Range 242.0 billion km (1682 days at full power)
This design is classed as a Military Vessel for maintenance purposes
It has a magazine and maintenance storage to act as a makeshift supply ship and collier if the combat fleet needs it. Also I needed to get it up to 10000 tons, hehe.
After some experimentation I found out that sacrificing power for efficiency will increase range on any engine. Probably because efficiency goes up twice as fast as power in those techs. So this ship uses an engine with more efficiency, my actual combat ships use power enhanced engines to get more power in the same amount of space, wreaks hell on the fuel supply though.
Now, I need to ask if this is normal, cause I'm building freighters with 8 armor thanks to this.
All of those except for Ymir are level 10 nebulae (250 km/s to an armor level). Either all those systems are in the same nebula or the RNG hates my guts. Luckily Nostrand there has all its JPs very close together so if I expand into Ymir later I won't have to worry about armoring the hell out of everything. (Ymir has 833 km/s to an armor level, much more suitable for regular ships).
Although the nebulae have helped me a little bit, some precursors (the blue systems) attacked me in them and I was able to deduce their exact armor level. Hell, I'm seriously considering living in this nebula cloud for all the defensive advantages they provide.
Also it appears that if you make your homeworld with 0.8 gravity, the universe becomes WAY more habitable, and dangerous, goddamn precursors.