Best colour 
Its fine on E10. Nothing to be gained from spending more.
Tyre pressures are written inside of the drivers door B pillar... set them then use the menu option to record them for the pressure monitoring system to work.
No you can't make the fonts bigger.... try changing the colours around. I recommend the dark mode (black background) much easier to read and at night doesn't blind you with a big white screen!
I just use regular E10 from Sainsbury’s and give it a dose of the Shell good stuff every couple of months.
As for tyre pressures, to my shame I hadn’t checked mine since I picked the car up a couple of months back. I checked them at the weekend and found them to be 36psi all round - the door sticker says 38psi. So, upped the pressures, and tbh, it’s like driving a different car, so much better. And that’s on cheapo Arnold Clark fitted tyres 😉