Print on Roll Paper

Hi. Trying to print on roll paper for the first time, and rapidly going hairless.

I want my prints to use as much of the paper as possible, without being cropped. So if I have a 2:3 image and I'm printing on (say an Epson 9900 loaded with) 24" paper, I want my image to be either 24"x36" borderless, or, with a 1" margin (for example), 22"x33".

I have tried all the custom and preset sizes, and Aperture so far has insisted on limiting the long dimension to 24" or 30" (depending on the setting).

Fwiw, I actually want to print w. a margin. And I want to print the full width of the roll (24"), and use as much length as needed.

Thanks. A quick reply is appreciated -- I'm trying to print now, and have use of the 9900 for another hour or so.

(I'm sure I'm doing something ignorant.) Thanks.