Holsters - CottonCarrier vs SpiderPro?

Hello:

I would appreciate any recommendations from holster users. I am currently looking at the Cotton carrier models and SpiderPro, but other suggestions are welcome. I would like something that can carry two camera/lens combos or which can be upgraded to carry two. The camera/lens combos I anticipate using are the 5dmkII with a 24-70L or 135L plus a Rebel or 7d with my 70-200F4IS. I might also need something that would work with a 300F4 lens in case I get one down the road. The anticipated uses would be: outdoor sporting events where I need two bodies (track, cross country, baseball); day hikes with one camera; light mountain biking, maybe skiing??; and just days at the zoo or whatever where my 24-70L/5d combo gets heavy for my middle aged sometimes problematic back :-). Many thanks in advance for your comments, pros & cons of each, recommendations, etc.

Jim Collett