I have a few clients in Cape Town South Africa using Windows Tablets. I found a nice Windows 8.1 tablet a few years ago with 2GB RAM and 32GB ROM if I can remember correctly.
The most important thing that I found is to isolate the WIFI for the tablets on their own Access Point. As soon as the shop becomes busy and customers use the WIFI then you have a lot of connectivity issues.
I also use Access Points that are a bit better than the ones for home use, something like Microtik to Ubiquity works amazing.
The only big issue is that there is a database connection time out or something that can cause issues when the tablet goes into sleep mode and then wakes up. I disable that function so the tablet stays on.
If you use the tablets as work stations then power shouldn’t be an issue. Just upgrade the charger to something like 3A+ on the charger. 2A that it comes with standard is to weak to charge the device while the screen is on.
If you use tablets for the waiters or more wireless then battery capacity will be an issue. When the tablets are not used get the waiters to put them on charge. The tablets that my clients use has 6500mAh batteries and they don’t last a full day.
I’ve tried RDP and it times out more than with a straight connection. There is hacks online available to remove the RDP limit for all Windows OS, but for me the RDP connection didn’t work well.