The base ISO is a 3-year old W7 Ultimate and I used NTLite to integrate 200-odd updates.
The test bed is an old 120 GB SATA HDD mounted in a new Asus 170M-Plus mobo with UEFI.
I won't detail all the headscratching I've had to do to get this DVD test system working (I'll be doing it finally via USB when I get a new flash drive), but it's finally installing and booting.
I've been deleting and wiping the HDD in between installs (MiniTools Partition Wizard) and I was surprised to find that the each install had been automatically done in GPT mode.
I'm not complaining, mind you - just curious. I'd always assumed that you get a choice in this. Like being asked 'MBR or GPT, sir?'.
Not sure I need GPT actually, the final system will consist of a 240GB SSD boot drive with a 2TB SATA storage drive alongside.