Best bet is to do a seat splice. Front portion of the XT seat grafted to the rear section of the TW seat. Adapting the entire XT seat has major fit issues with regard to its shape. So yes, if you can get them together it would be worth it.
This is the only clear pic I have of mine. XT front, TW rear, mostly XT foam, covered and stitched by a local upholstery shop (The dudes to the left and right of me were just a couple of homeless hippy panhandlers on a work release program)