I wouldn't call any of Rothko "squares," the canvases were more likely to be tall and elongated in his later painting. The Seagram Murals were painted to fit into spaces and I haven't found all of them an line although the Simon Schama -- there were several large horizontal rectangles.
I posted what oils he has painting and could find nothing in the sizes you're quoting. To my knowledge in two full courses in modern art, there are no Albers in those sizes and he kept the basis proportion of the image being slightly higher than wider, leaving a larger space at the bottom or top of the image. The larger painting must have been loaned to the National Gallery bit I have no idea where they came from as I couldn't find anything larger than 48" x 48" in my Albers book nor online which wold be dwarfed by nearly any Rothko.
Well, Amigo, like Pollock, DeKooning and the rest of the abstract expressionists, the scale of the work is a very important aspect of their work. Small reproductions are not as the artists intended. It's almost like a wide screen film being shrunk to an 8" screen. In that case, the wide screen often is pan-and-scan which cuts off parts of the left and right hand side of the film. The impact in small reproductions is virtually lost.
An Albers at Hirshhorn from 1966, after Rothko's death.
http://hirshhorn.si.edu/collection/record.asp?Artist=Albers%20Josef&hasImage=1&ViewMode=&Record=11
Not only would I not call 4' x 4' huge, I wouldn't call a painting 3' x 5' (out of proportion to any Albers I know of) huge -- maybe a good size for over a sofa!