Try your B-1. It will be great. Nice mic, and if you want to turn down some of the 'air' just roll the highs off a little with EQ.

No need to buy anything else. The MD-421 is a great dynamic mic, and I had unhindered access to the model II version for about 5 years before I moved out of state and returned it to my church that never used it.

I have a Scarlett 18i8 and I'm guessing the pre-amps are similar. They have plenty of gain for my cheapo LDC as well as an EV PL80a (which I like plenty as a bit hotter than an SM57/58) and an EV SRO RE11 (old school mic - I need to get a clip for it) and the Scarlett 18i8 works fine with all of them.

I used to use my LDC (CAD M-177) almost exclusively for vocals, but I've found that the EV PL80a is much more forgiving for crummy room acoustics and I even like to use it on my acoustic guitar - though it's marketed as a vocal mic.

I think you will like the B-1 just fine with the Scarlett. What did you use before with the B-1?