R500 anteannas offer more coverage, as H500 is designed to cover one room (with additional LAN ports).
Sitting horizontal on the floor under the nightstand (or horizontal mounted from ceiling in the closet) would probably provide better RF radiation pattern than wall mounted. Concrete walls with rebar can possibly block penetration to the next room(s), so do test with a laptop site survey at least, as you evaluate final locations.
Disagree with Michael on H500 use case. The H500 is an 'in room' AP as in it is designed to be wall mounted, has additional LAN ports and is physically smaller. I disagree on the coverage. No AP with EIRP of 19 & 23 DBm is designed to cover a single room. It's purpose is to allow the AP to be closer to the user and provide additional LAN services.
I have regularly installed these in hotels where the ratio is 1:3 and even up to 1:5 depending on construction.
I have also installed them in every room but have found that I need to turn off the 2.4 radio on 50% and even the 5GHz on some.
As for the R500, if you wall mount it the you have to appreciate that you are changing the AP footprint from its optimal. You will see less signal horizontally and more vertically. That said the AP had PD-MRC so performance shouldn't suffer as a result just coverage.
There is a Ruckus doc on AP mounting. I'll find it and post a link.