Having worked majority graveyard shifts in the past, I gotta say: don't. At least not for long term. One day off is not enough to shift your body from night to day mode or vice versa, and having to do that on a regular basis, even with two weeks off? Extremely rough. I can say, anecdotally, that I was running off caffeine and sugar for a lot of my shifts, and it definitely affected my mood and ability to do things (even for fun!) on my days off.

Three weeks in a row working is also gonna be rough, but at least it will be a steady-state exhaustion rather than trying to readjust your body's clock.

I'd think the deciding factor should be how long do you expect the schedule to stay like that? You mentioned that you expect to be eventually promoted out of night shift?