List of potential colonies:Giclas 99-49:Giclas 99-49-A III - Moon 2 Colony cost: 3.11
Giclas 99-49-A III - Moon 6 Colony cost: 1.90
Gliese 686:Gliese 686-A I Colony cost: 7.39
Gliese 686-A II Colony cost: 1.90
Gliese 686-A IV Colony cost: 4.07
Gliese 686-A V Colony cost: 5.38
Gliese 686-A VI - Moon 5 Colony cost: 5.74
Gliese 686-A VI - Moon 14 Colony cost: 5.95
Gliese 686-A VII - Moon 4 Colony cost: 7.07
Groombridge 1618:Groombridge 1618-A I Colony cost: 3.12
Groombridge 1618-A III Colony cost: 3.74
HIP 25578:HIP 25578-A V - Moon 6 Colony cost: 6.26
HIP 25578-A V - Moon 11 Colony cost: 6.85
HIP 25578-A VII - Moon 9 Colony cost: 7.46
Procyon:Procyon-A I Colony cost: 2.03
Procyon-A II Colony cost: 1.90
Procyon-A II - Moon 1 Colony cost: 1.90
Procyon-A III - Moon 10 Colony cost: 6.54
Procyon-A III - Moon 19 Colony cost: 6.31
Proxima Centauri:Proxima Centauri-A I Colony cost: 1.90
Proxima Centauri-A IV - Moon 2 Colony cost: 6.47
Proxima Centauri-A IV - Moon 16 Colony cost: 6.20
Proxima Centauri-A V - Moon 1 Colony cost: 6.55
Proxima Centauri-A V - Moon 16 Colony cost: 6.40
Proxima Centauri-A V - Moon 27 Colony cost: 6.91
Proxima Centauri-A IX - Moon 4 Colony cost: 7.68
Proxima Centauri-A IX - Moon 5 Colony cost: 7.73
Sol:Sol-A I Colony cost: 13.02
Sol-A III - Moon 1 Colony cost: 1.90
Sol-A IV Colony cost: 1.90
Sol-A VI - Moon 5 Colony cost: 3.92
Teegardens Star:Teegardens Star-A VI - Moon 48 Colony cost: 6.49
Teegardens Star-A VII Colony cost: 7.44
Wolf 294:Wolf 294-A I Colony cost: 1.90
Wolf 294-A IV - Moon 4 Colony cost: 6.25
Wolf 359:Wolf 359-A I Colony cost: 6.54
So from what I can tell it seems that Procyon and Proxima Centauri would be good for mass colonization whereas I have noticed that Ross 47 is just like a hub of jumping to other systems.