I have stuffed 2 tubes with tire levers in one and multi tool in other on back rails of saddle between back of saddle and the delta winge. I used 2 x-lab straps (I think they are called utility straps?) that I used to use for my old carbon wing. works pretty well and I think it is protected from the wind pretty well. I'll try to post a picture. I put CO2 and adapter in my jersey when training and I think I will put in my stealth pocket when racing.

Candice, would the x-strike work with the delta sonic? If so, that would be a way to carry CO2. Also, I have an carbon wing that I used on my old P4, is there a good way to attach this to the P5? The seat post doesn't have the holes to attach to like the P4. I plan to use 2 rear bottles for IM distance races, 1 for anything shorter.