With QGJ getting same tier gear as Boba on 65lvl, it's safe to say they're on par throughout 65-70 lvl (neither gets tier8 done).
If you count all energy then its 120 basic +45 midday bonus +240 refills + free level up energy (roughly around 15-20 if you average it throughout 1-70lvl). So it's 420 daily (lets take floor here). Doing the math properly it's 628 shards daily. Of course thats assuming you're diligent and meticulous. After some magical math it rounds up to 43 days to get a full unit from scrath. If you get 2 additional shards from nodes then it's shortened to 36 days.
So my initial math was a bit off, because of that 5 days of double cantina energy (hope they'll make it monthly event). Thanks for pointing that out. It would be possible to get him fully farmed around 70, as you pointedout.
Edit: Saw you added smth so wanted to chip in. I assume anything below fully unlocked QGJ is kinda subpar since his stats aren't so great. In case of Boba, he does preety well with 5-6*. You could easily decide then if you want to switch to QGJ.