Hi Fun Photons.
I have a pair of the optech rain sleeves, I bought the ones for a moderate zoom, figured that with a shorter lens it could be scrunched up, only used it a couple of times plus a trial fit to familiarise with fitting it so as not to be fumbling when the camera needs it! I have also shot out in the rain, 7D and 17-85 by shoot and tuck inside the coat technique! I have also been caught in a deluge and just put it in the bag and pulled the AW cover over the lot!
I would suggest that if you are going to use the camera regularly in the rain you get a better system than the optech, not for any reason other than it is thin poly sheet and with regular use may become weakened and would probably puncture more easily than some of the heavier offerings, either that or treat optech as limited use items and replace them when there is any reason, at <$10 a pair they are pretty much in that category!
Recommendations for a good "Camera Condom"? You know, these various bags you can get to cover your camera for bad weather.
7DII+Grip, 7D+Grip, 40D+Grip, 5D+Grip, EF 24-105 f4L EF-S 17-85, EF-S 10-22, EF 70-200 f2.8 L IS II, EF 2x III, Σ150-500, Σ17-70 f2.8-4 C, EF 50mm f1.8, 550EX, Triopo TR-985, Godox FC-16, Filters Remotes Macro tubes Tripod heads etc!
5D, 20D, 24-105, BG-E4, BG-E2N, 17-85, Nifty 50 pre owned. 😀