Hey man, don't worry too much about it. A buddy of mine lat moved straight into Recon from the Marine Corps band as a sergeant, and my unit sent him to SOI and Recon school without too much trouble. He's picked up SSgt since then, and he's operating as a TL in my platoon. He's not what I'd call experienced in recon, but he's a good staff NCO, so it balances out.
As for your promotion, since you're broken service like me they won't have much of a history on you as a sergeant and therefore won't have much of a fitrep to report. Your chances of a fast promotion are slim. You've got plenty of time.
On a side note, I don't understand why you'd waste the time going through a lat move to 0351 and then having to go to school back to become an 0321. Why not just lat move straight to 0321? It's gotta be easier to do on paper. Just get in touch with the Hawaii Det. or the guys in Alameda. They can get your package started.
Just a side note though, I hear that they just got back from a really fucked up deployment and most everyone worth a damn has left the unit. That leaves a lot of openings for you to fill, but doesn't say much for the commanders out there.