Thank you very, very much for your reports on low-cost hardware. Please keep us up to date in this forum on how these tablets hold up in the field and how students are able to work with the 7” screen.
I tested 40 Kio Tablets from BRCK in South Sudan, but I was only there for two weeks of testing and there are problems with recharging. The screens did not seem to be a problem, but most of the testing was just Khan Academy videos and exercises.
Consider remedial classes outside of the normal schedule which often does not allow enough time to set up and use Khan Academy. Consider also taking a document camera to use with a laptop and a projector.
The simple browser included with Android was faster for us than other browsers.
You should consider installing some of the free Android Khan Academy Math apps from Google Play so students and teachers can work outside of the range of you RACHEL-Plus server.
Best wishes, Ed