Are all stars outside of the first ring eventually (within a month or 2) going to supernova? Are new stars forming here? I can't really build a fueling station in past the 1st ring, unless I have a ship nearby to pull up the stakes quickly enough, I suppose--if i want that station to survive (they are expensive...)?
the size of star depends on how fast it goes nova.
Giant stars go nova fastest, on aveage about 2 months
bianary stars are second fastet
colored stars are next
dwarf stars last the longest (6+ months)
so for your refueling station, pick the dwarf star that is the most stable (closest to zero.) You will still need to move it a couple of times a year, but you will be notified by PM and have a week to complete the move.