Prior service 11C reclassing to a Bravo. Any tips?

They are going to teach you everything and your only a SPC, so I would not worry about it. I wasn't a pure 11B either but so much overlap between then 11H (TOW) and 11B it was practicly one in the same our movement was on jeeps but almost mimiced exactly the movement on foot at times. We also parked the jeeps and did purely 11B stuff on foot as well. There really is not that much additional stuff to master beyond what you know as a 11C already. Just tactical movement which you should know as a 11C, Patrolling, and assaulting / clearing buildings and bunkers.

I think it's the same for both MOS's, I was FDC in an infantry unit and I was 11B, we still humped around, but with the 81's, that tube and base plate was heavy. At Bragg, I used to jump out with three 81mm rounds tied to me.

You’ll be good. Just do what your leadership says, and take every training opportunity you can get.

It sounds cliche, but train how you fight and muscle memory are both very real and effective things.