Try before you buy! The 8500 POs are very thick, plenty of people say too thick. The 45.5 is a big beast of a watch, which I thought wore better on rubber than steel when I tried it. Ultimately its down to what you feed comfortable wearing, but I wouldn't gamble on the size if buying new as you stand to lose a fair chunk if you sell it on after paying retail, £2500 is about what they go for on Sales Corner.