Decision: Fenix 6 or 6S?

So I had the Fenix 6S Sapphire for a year but it went back under warranty due to an issue I had with it.

I have the money now to buy another watch but should I use the opportunity to go bigger? I have a 16.5mm wrist. I tried on the Fenix 5 a year ago but the main issue I had with it was it would always spin around my wrist when I got really sweaty and the watch face would end up at an angle. Will the 6 be any different with the slightly reduced weight and thickness?

The Fenix 6S worked well for me running but the screen is quite small for map reading when hiking, plus I fancy a change. Should I play it safe and stick with the 6S since running is my main sport? Does the 6 look too big for my wrist?

I can buy a 6S Pro (gorilla glass) for £499 or the F6 Sapphire for £599.