I pulled some numbers on travel times (Legends about the Millenium Falcon point A to B) and did some math, the number I came up with that I use in my games is 6 hours for every inch on the EotE Galaxy Map (at class 1). Threat/Advantage to then further adjust the times. (in map squares, that's about 3 3/8 hours) The way I accommodate shorter travel times on established hyperspace lanes is to simply grant Boost/Setback etc. depending on the situation rather than adding some sort of multiplier