Mark;


Your lens setup has the 10mm - 400mm pretty well wrapped up. What will you be using 70-200 for that the 24-105 and 100-400 won't cover?


The 70-200 is a pretty expensive for redundancy, unless you're shooting (a lot of) indoor events, then the 2.8 is your answer.


But if this isn't the case, go for a big prime.


Regards


Bill