I agree with ariell, I got the same response from CIC. So I sent them everything. The box weighed 10 lbs. Sending a large amount of proof can't hurt you in my opinion. The trick is to avoid them not being convinced and asking for more proof. I didn't want that delay so they have everything. If they don't need it all then that's fine. This is the most important thing in my life right now, so I wasn't about to hold back. To qualify, though, everything was very well organized and detailed. Chat records organized according to month in their own manila envelope, 150 pics with writing on back indicating what and who is depicted, and lots more. This way, they can choose how much they want to read but they certainly won't be asking where the proof is.
That's my opinion but other members might have a different opinion. I would lean towards opinions of those who were approved without delay or requests for further information. If you look on trackitt, you will see a high number of folks who were asked for further documentation. I did a lot of research before I sent mine to Mississauga. I built the application with the mindset that absolutely nothing could be requested because there is absolutely nothing missing and our marriage/relationship comes across as obviously genuine.
In my opinion more is better as long as it is all relevant and contributes to painting a clear picture of a genuine relationship/marriage to the IO. If you feel that you can paint a clear and convincing picture with less, then I would say that is better. For us, we had a few flags (i.e., a short time from meeting to marriage and age difference) so I felt it was better to give them as much as we had. I suppose every case is different. I would simply look at what you are planning to send and ask yourself if it comes across as very convincing that it's a genuine marriage/relationship.
Bottom line, sending a lot can't hurt you. Sending a little can. Let them have it. They asked for proof, so give it to them. A lot of applicants get requests for further proof. Avoid this request and avoid a delay.
Just my 2 cents.
Cheers