If you really want to play with sequences, shoot half-frame 35.
I say that only half in jest - I've printed half-frame sequences with my 4x5 enlarger (LPL 4500II). With full-frame 35, 3 frames is the strict limit for enlarging at one time, as neither the negative carrier nor the enlarger head that it sits in can fit any more than that. Beyond that, I find sequences of vertically-oriented frames hang together better than sequences of horizontally-oriented frames, though that's a matter of personal taste, YMMV, etc.
EDIT: It's possible I'm not correctly understanding what you're trying to do. How would you like the print to look? What do you mean by "Used a custom smaller carrier within a larger carrier"?