@nmalinoski – Sorry, I wasn’t particularly clear, there. I used Enigmah to alter the region to NTSC M before testing with the SCART. With NTSC M/SCART, it’s 480i or nothing, essentially. Enabling 480p win that configuration and then rebooting, results in the 480p setting changing back to “off.” So I assume the console is limited to 480i/525i over SCART.
With the region set to NTSC M and the console hooked up via component, I can enable 480p or even 720p (not that I need to go that far!) and it all seems to run just fine. There are faint diagonal lines going on in scenes with large blocks of colour, but unless there’s an easy fix for that, I’m not massively bothered by it. 🙂
Just waiting on a Dreamcast RGB cable (since the Elgato Game Capture HD60 Pro is kicking up a fuss with the Hanzo and OSSC) and my setup will be complete! 🙂