I've had my 6D since July so thought it time to find the 6D thread.
Personally I don't see the point in the Canon 24-70 f4L. If you want that focal length you might as well get the f2.8 L (for more money admittedly) or the Tamron 24-70 f2.8 VC, which gives you images stabilisation and f2.8 for less money. The 70-105mm end of the 24-105L zoom range is really useful, even for landscapes. And at 105mm it does a lovely job of portraits.
For the money, you get more bang for buck with the 24-105, it's much more useful.
I have a previous version of this Manfrotto
https://www.amazon.co.uk/Manfrotto-...d=1480782994&sr=1-5&keywords=manfrotto+tripod
I bought it when I had a smaller camera, but I still use it now.
It says the limit is 1.5Kg, and I've had my 6D with 24-105 on it fine, even when standing in a shallow river. Though I wouldn't want to put a longer lens on it.