I'd spring for the cerakote just out of the fact it will protect your investment better then parkerizing. I carry Detonics Combat Masters [1911 derivative] one in Stainless and one Blued. The Stainless is not "corroded" but is stained and worn from holster and sweat and the Blued one the finish has seen a lot better days. I intend on getting the Blued one cerakoted. Save yourself some headache and get your RIA cerakoted
By the way Gainman he is not talking about carrying a full sized 1911 but instead a RIA Compact
This is very similar to size of my Detonics and I have no particular problem carrying them and I'm about the same size as he is. I've put my Detonics next to friends Glock 26 and XD and there really is not that much difference in size.