If you’ve got a dog in the health care reform fight, you might want to keep this weekend open for another nail-biter vote — this time in the Senate.

[IMGCAP(1)]Majority Leader Harry Reid (D-Nev.) is hellbent on getting the debate up and running before Thanksgiving, but he also wants to try to give Members next week off. Problem is, he’s still waiting for the Congressional Budget Office to give him the magic numbers on how much this legislation is going to cost.

Democratic leaders told staffers Monday they expect that CBO score to be ready today. But even under the most optimistic scenarios, Senate Democratic aides said the chamber would be unlikely to vote on whether to start debate before Friday, and several said a Saturday or Sunday vote was more likely. Just over a week ago, the House narrowly passed its health care reform measure on a Saturday.

Either way, Reid wants to be able to roll out the measure to the full Democratic Conference on Wednesday, with an outside hope of briefing Members today. Even if he gets the CBO score today, Reid probably will have to wait until at least Wednesday to start the clock ticking on the time-consuming and arcane procedural maneuvers he has to set in motion before the official Senate debate can even begin.

After all, Republicans are intent on trying to filibuster what is known as the motion to proceed to the bill, a move that if successful would prevent the Senate from considering or amending the measure. Reid needs the votes of all 60 members of the Democratic Conference to succeed, because 60 votes are needed to kill a filibuster.

But to get to 60, Reid may have to let the bill sit for a 72-hour review period that several wavering centrists, including Sen. Blanche Lincoln (D-Ark.), have asked for.

Aides familiar with the Democratic leadership’s thinking refused to say how long the bill will be available before the vote.

“We’re confident Members will have all the information they need to assess this bill before we take it to the floor,— was all one senior Senate Democratic aide would say.

But another aide said Reid would definitely “need to leave some window of time between presenting the bill [to the caucus] and bringing it up for a vote.—

Even if Reid ignores the 72-hour request, just filing the motion to limit debate, or invoke cloture, requires a two-day wait before any vote. Filing a motion Wednesday, for example, would set up Reid’s optimal Friday vote.

Lincoln’s request, however, could be no small matter, because she appears to be the squeakiest wheel in the Caucus at this point, given other “undecided— Democrats now appear unlikely to vote for the filibuster. Sen. Ben Nelson (D-Neb.), for example, has not committed his vote, but he has traditionally been loath to prohibit the chamber from even debating a measure.

“Until people cast their votes, there will be regular minding of the United States Senate,— another senior Senate Democratic aide warned. “I don’t think you lock up any votes until they’re cast.—

The message leadership has been sending to fence-sitting moderates is that the delay in the debate over the Thanksgiving holiday should satisfy their demands that the American public be given enough time to review the bill before the amendment process starts when Congress returns on Nov. 30.

Plus, aides are making clear that Reid’s mash of a Senate Finance Committee measure and a Health, Education, Labor and Pensions Committee bill is not written in stone.

“It’s really just a starting point for negotiation with some Members to see what they need to secure their votes for final passage,— one Senate Democratic source said.

Meanwhile, it appears that Reid has been receiving some initial numbers from the CBO, and those numbers are not a cause for alarm.

The second senior Senate Democratic aide said leaders are “confident— the bill will get “a good score.—

The Senate Democratic source added, “I don’t think [Reid would] be going ahead with the process if he had a number that was out of whack. … I’m sure it’ll be in keeping with the president’s stated goal— of $900 billion or less.