I just wear OWB when I'm on both my bicycle or my motorcycle. A good quality holster with a good quality belt as well as some form of retention and you should be fine.
Specialized just released some new jerseys that are awesome. In the middle pocket on the back they have made it a "double" pocket. There is a sweat shield separating the inner pocket and outer pocket. Would be nice for a small pistol. There are in stores but the website isn't updated yet.
I typically either use an OWB or pocket in my jacket. I'm an ATGATT person so shoulder holster are gonna leave my rig nice and sweaty in the heat so I don't use them. If that's not an issue for you, then I agree shoulder would work.
But as some others have mentioned, whatever you are using now will be just fine.