Firstly, I am new to all this too, so take my advice, or leave it, with that in mind!!
I have recently rooted mine from the AMG3 build with mskip's toolkit. I took the plunge and took his advice on choosing the closest available build. I donated so as to be sure I had his latest update of the toolkit. I am not near my pc, but it was the selection which included the AMD3 build (the most recent, ie bottom in the section for the model with NFC, as that is themodel I have). I had one root through odin which failed to give superSU any binaries or permissions at all, so then completely reinstalled the toolkit on my pc (possibly unnecessary) and then reflashed twrp recovery, but chose the cwm version of superuser and ot worked perfectly! As far as I can tell, my phone works exactly as it did before, but now with root access.
If you look in this section of the forum, I posted a q this morning which gives a couple more details about the process I went through re 1st failed attempt which I won't retype here, but I can confirm I have full rooted functionality with the toolkit over the AMG3 build on the N model of the mini, with twrp and superuser!
Btw I say a failed attempt, but my phone worked fine, I just got an error message at the end of the toolkit installing busybox, so booted the phone and superSU just said "there are no binaries I stalled, this is a problem!". So I assume I wouldn't have been able to exploit the root, but at no point did It stop the phone working as a phone.
As I say, I am faaaar from an expert, but that's my experience.