I was in the same predicament. There are no places that rent rifles, at least not around me. I found info on recoil and used recoil simulator/calculator programs to guesstimate. I talked to family and friends and shot a few rifles in different calibers to get the feeling for it as well, there simply is no substitute for that hands-on.
I will also say that caliber choice is mostly dictated by use, as certain calibers are just meant to be used on certain size game, as an example.