The size is 9.5H which roughly translates to a 10.5D/E US Brannock sizing. H is RM Williams' "wide" width. Unfortunately these are just a bit too short for my 11D foot.
The Dynamic Flex model differs from the Comfort model in that it has a combination leather/rubber sole versus the full rubber sole of the Comfort model. In addition, it has removable insoles with great arch support (or allows you to put your own insoles in if you need).
These were worn for a single day in an office in attempts to gauge fit. Sadly, they won't work for me.
The nutmeg color is currently on a 2+ month backorder with RM Williams and this specific leather on this sole is an Australian retailer exclusive and unavailable through RM Williams or in the US.
Retails for $545AUD. Asking $395 shipped CONUS.