Eileen here. I would personally recommend going with 45 calendar days because this is what the OB476B says as well as the cover letter. Msafiri, I wasn't able to find the RQ deadline in the updated CP4 policy manual, so please let me know if I'm overlooking it!
I believe that the RQ form itself still states 45 business days (recent recipients: please correct me if I'm wrong!), but my understanding is that OB 476B is the governing document and reflects the official policy.
Just make sure to send something in by 45 calendar days and include a letter listing the documents that will follow later. It's impossible to get all official documents (especially the OHIP PCH or official records of movement) within 45 calendar days. The important thing is to send some response to CIC so they can't claim that you failed to respond to RQ and close your file.
I got my RQ right after the issuance of OB 476, and 45 days would have made my deadline December 26th, so I sent a letter entitled "Intent to Reply with 45 business days in accordance with OB476". While OB476 is no longer valid, I recommend that if you can't send any documents at all by the 45 day deadline, you could send an "Intent to Reply within 45 business days in accordance with instructions on CIT 0171 (09-2012)" (though please verify that there haven't been any secret updates on this document first!).
As Msafiri says, it's egregious that the CIC is still confused about something so basic as the deadline for the RQ. As it is almost 2 years after OB 407, the CIC has had ample time to resolve this. One can only assume that they don't want to resolve it.
That speaks to a lack of respect for the applicants and the citizenship process. This translates to a lack of respect for citizenship. When someone cares about something, they don't leave a typo about such an important element for 2 years straight. Imagine if John A. Macdonald's name was spelled Jhon B McDonlad on the $10 bill. Would the Mint just kept printing it that way for years? Would they say "Oh whatever, it's not that important."
I don't think so.