I am using ultragauge with a 6" tablet.
Traveling thru US and Canada these gauges are pretty handy. Still can't convert liters and kph very easily in my head. Most Canadian fuel pumps require prepay so you need to know about how many liters you will need so you don't over estimate. Charge stays on your credit card until they submit info to the CC company. Usually about a week.
Have uploaded 3 of these screens to the ultragauge web site for free download.
You may notice I have settled on a white background with black gauge detail. Seems to be the most readable on sunny bright days. Should be handy for Canadian snowbirds coming our way in the winter.