Converting FT offer from one division to another after summer internship

Hi everyone. I think that I have a decent chance of getting a FT offer at the end of my summer internship (US bank in London) in my current division. However, I'm interested in converting my offer to IBD - I have a few options, but I can't decide which is most optimal - any advice would be appreciated. Thanks.

1. Inform HR prior to the end of the internship about converting the offer - I forfeit any opportunity for FT in my current division but get fast-tracked for an IBD interview (if headcount allows).

2. I inform HR after (if) I receive my offer - I don't know the protocol for this option (i.e. if they would fast-track any FT interviews or just withdraw their offer entirely).

3. I receive the offer and apply to other banks for FT - the problem is the time I'd get to accept my current offer; from what I've heard it's likely 2 weeks, and some banks don't even open recruiting for FT when the deadline hits for accepting this offer.

4. Same as 3, but I apply for another SA role but this time in IBD (and then start off-cycle or complete a master's).

5. I take my current offer and look for an opportunity to convert after completing the graduate scheme in my division (I by no means dislike what I do currently).