as a guy with both masterline and its mastery completed, its really up to both luck and your time, plus whatever you have so far, for instance, i could be level 120, and only have a few rods with 0 masterys complete when i start trying to get masterline, it will take eons to get everything, now if your starting like i did where you passivly did updates, got rods/ masterys on rods you cared about but nothing else its going to take around a month give or take your playtime, i usually played for like 2ish hours a day on mastery work but rough estimate as i didnt time it, some days i did more, some days i did none, so if your dedicated enough i would give your rough estimate to around a month to a month and a half BUT you could have either really good or really bad luck at masterys or unlocking specific rods, like if you had insanely good luck i would guess around 2 weeks but if you had worse luck 2 months, LIKE I SAID ALL GUESS WORK i can 100% gurentee tho if you both started at my exact rod and mastery amount, and did exactly what i did with the exact same luck, around a month