To give my input on the GMK vs SP discussion:
One big reason to go with GMK over SP is their thickness of caps - SP caps are much thinner than GMK caps.
However, SA profile caps are super thick. I don't have a full set, just a few from a crap bag, but the caps I have are quite thick and wouldn't feel "cheap" like some people think DCS SP keycaps feel. So since the general consensus here is to go with a retro looking style, I think it'd be best to stick with SA profile from SP since it gives us that profile, centered big alphas, and still is thick.
Just my two cents.