I have Maggie 1.7s as well. My room is 18'x12' but since I have many, many components, my 1.7s are on the 18' wall instead. Here are some things I have found.
My Maggie's aren't in the corners, they are centered along the long wall and are only separated by 6' on the inside edges. I don't have a lot of depth. If you can move them a little closer together you might try that because corners can muddy up your sound. Especially, with Maggies pumping out music both front and rear. If you have to have them that close to the corners you might have to look into some Bass Traps to tame some of the reflections. I would suggest you google "bass trap" and look for GIK.
While 5' seems to be the optimal distance for Maggie's to be pulled out from the front wall, your distance could work very well. You might try them pulled out a little further, if possible. Mine are only 3' from the wall but I still get a great sound.
Two things I do that are a little different: 1) rather than point each of my Maggie's at my ears, I angle them so they point about 6" out from my shoulders. This gives me a slightly differant sound which you might like also. Especially if your chair is close to your Back wall. Try a few different angles. You may find a surprisingly nice placement you like better than having your speakers pointing right at your ears.
2). I like my Maggie's to be tilted forward 1 degree towards my listening position rather than tilted back. You might try few different angles (forward leaning, straight up or backward leaning) to see which one of them produces the sound stage you enjoy the most. You might try some different size pieces of wood to help provide an angle and don't forget, you can always mount the Maggie supplied feet reversed which will give you a forward lean - if you like that sound. No matter what you use to stand your Maggies up - the regular issue Maggie feet, Mye Stands, or Sound Anchors, I would suggest going to your local Big Box Hardware store and buying a couple of those large, concrete patio blocks. The ones that are about 15"x 15" or maybe 18" x 18" and are 2" thick. One or two of those on top of your speaker feet will anchor your Maggies as good as anything.