On your ICC profile downloads, there are a few profiles that say, (For small margins). These profiles tend to be associated with the acronym MPP (matte photo paper). What is meant by, "For small margins" and is there some connection between this and matte photo paper?

On Canon printers, if one uses a 'fine art' media type the quality is a 100 but the margins, especially on the bottom, are too much for some people. So we created additional profiles which use a different media type. These media types provide for smaller margins, however the print quality is just a smidgen better with the original 'fine art' media types.

Having trouble utilizing the small margins profile for the Entrada Ragg.
Using a Canon 9500 MKll and Photoshop Elements 9.
Loaded the ICC for Entrada Ragg small margin. ICC is selected within More Options/Color Management/Printer Profile. However Canon still forces a choice of "Art letter (Margin 35)" and does not allow me to use small margins for an 8.5x11 print. Color handling and rendering intent are selected as PSE and Perceptual. "Source Space" is not a selectable option.
Very much appreciate your input.
Thanks

You should be able to use a different media type, Matte Photo Paper, that is the key to allowing you to use the smaller margins. If you use the Fine Art media type the printer will force the wider margins on you, as they are afraid of a user damaging the printhead.