We just got the new Kindle Fire HD 10 (2017 model) to replace our iPad 4 that just became obsolete with the release of iOS 11 (we've had no end of troubles with it since then). The Fire is running Android 5.1. The UC Surface GUI is extremely small on the device. It's not unusable, but it's nearly unreadable. Having some sort of scaling option might be useful for the mobile versions of UC Surface, something like 0.5x, 1x, 2x, etc options for interface scaling.
[EDIT 10/28/17] I've uploaded a picture of the issue. This is the Kindle Fire HD 10" tablet, next to our iPad 4. The size of the GUI on the Kindle is unacceptably small.