I have just bought a sailproof 8 inch as well. Very good tablet pleased with the purchase. Please see picture. It is in an aluminium ( home built) cradle and stuck on at the moment until I am happy with the arrangement. I have it connected by wifi to the raspberry pi and get NMEA traffic as much as Navionics can handle. I also attach it to my phone via bluetooth so can get internet. Useful for Navily.
On the tablet I have : PredictWind, Imray Tides, Solentmet, Met Office, BBC Weather, Royal Navy tides, Navily, Sail Expert.
For charts I have Imray (comes with the paper charts) , Navionics ( paid subscription). I tried out Aqua Map and Savvy Navvy but they did not seem to have a lot of detail especially when anchoring. I like paper charts and use them a lot but not sure raster works with small screens. However I do like the clarity of Imray and it provides different info to Navionics so having both is a plus. I would like to see how AngelNav works when it comes out on Android. My goto apps are Predictwind and Navionics but use the others for specific purposes.
The tablet can be seen in the cockpit, close enough to adjust size of map, last the whole day - what more can you ask. I have removed the 3 screen navigation buttons and use gestures so get a full screen. AIS is a pain and I tend to filter it. Too busy in the Solent. I expect much better when in the channel/outside Solent. Not sure whether it should be landscape or portrait. Would welcome advice.
My phone, a Galaxy S20+ ( hand me down from my son), has Samsung Dex. This is brilliant. I network this ( wirelessly) to a Samsung Dex program on the Windows 10 PC. I can then project Navionics ( or any other app) on to my 23 inch screen and create routes which is much easier with a large screen, keyboard and mouse. They automatically get sent to the Sailproof.