A skagit line should work very well on that rod. Skagit lines handle tips no problem. I have a 7136 that hates tips with any normal line but with a skagit rig I can launch big flies and heavy tips. I would guess the 450 Rio line should work but it may be a bit too heavy. I know I've seen lots of posts from people who like that match up on Speypages. See if you can borrow one from a friend or demo one from your local shop.
I have a Loomis Skagit Dredger 13' 9". I make homemade lines though, if you get yourself a grian scale to weigh lines, or just look up the grain weight of a certain weight line on the net, you can tailor lines by buying in bulk and splicing spey lines if you want to taper like the Rio Skagit. Your suppose to make a belly aprox. 2 to 2.5 times the rod lengh. So for my dredger, 13'9", I made my belly from about 15 and 16(for a front taper) weight lines spliced together to make a 27 foot head which was then attached to Cortland Cobra running line. So instead of a hundred dollar line you can get away like a theif in the night Also, I find these homemade lines cast as good or better than the Rio Skagit heads, and form just as pretty loops.
I have the Rio Skagit 650gr 9/10 line on my 9132 Loop Blue. I have changed the running line to 50lb Slickshooter. For me this works awesome, really shots the line if thats the style of casting you want to do. I also had a 7136 Sage but it didn't like tips at all, but never tried the Skagit line on that rod.