That's the bottom line.
Seat Al Franken and give him his committee assignments now, or we'll block a new organizing resolution that would let you reassign Specter's previously Republican committee seats to one of your own.
Until a new organizing resolution is adopted, Specter's committee seats (Appropriations, Judiciary, Veterans' Affairs, Environment & Public Works, Special Aging) are locked in. He'll be caucusing and (sometimes, anyway) voting as a Democrat, but will be occupying Republican seats.
Democrats should demand Republican agreement to seat Franken and give him his committee assignments now, or they'll just block a new organizing resolution until he arrives, and change it as they see fit later on. After all, with 60 Democrats (once Franken is finally seated), they can give themselves any ratios they want, whether they opt to remain true to the 60/40 split in the Senate or not, since there won't be enough votes to filibuster an unfair organizing resolution.
But we wouldn't want it to come to that, would we?
Until there's a change, Appropriations goes effectively from 17-13 in favor of Democrats to 18-12. Judiciary to 12-7. Environment to 12-7. Veterans' Affairs to 10-5. Special Aging to 12-7.
I guess we could wait if we had to. Those are mostly ratios we should be getting once Franken is seated anyway, even without exceeding the ratio of Democrats to Republicans in the body as a whole. So it's not even like we're taking any more unfair advantage in doing this than Republicans are by denying Franken his seat.