Magnepan 1.7 speakers (asking for a friend)

My room was smaller I had them 28" from the side wall tweeter in toed in 38" ( mid bass section)and 30"( tweeter section) from the rear wall

Don't have the 1.7s but had the 1.6 and now have MG12 with highly modified crossovers . 

Maggies have come a long way from their beginnings . 

Maggies have to be at least 4.5 to 5.0 feet from back wall . At least 3 feet from side walls . They like asymetrical positioning . Spacing the speakers depends on sitting position . You open them up you get a marvelous big soundstage but with less focus images . Get them closer and images are better focus with more specificity . 

Having said that maggies don't focus as boxed speakers . Image outline are a bit more homogenous .

One thing which is extremely important and seems to be a caracteristic of all the models I've had is that moving them around seems to deterioate one aspect of performance while getting another aspect better . You get them closer and you get the bass punchier and impactful but will lose spaciousness or focus 

Maggies are speakers that dictate where they want to be and always need space to sing . The difference can be stunning . Take care and stay safe .

I had the 1.7's in two different rooms, one larger and one smaller than yours.  In the smaller 13x15' room, they were nearly half way out into the room and I sat right against the rear wall.  Great imaging with bass reinforcement.  In the larger room room they were roughly 1/3 out from the front wall, I sat 2/3 from the front wall.  Equilateral triangle arrangement.  Worked very well also.  The critical thing is getting them off of the front wall (the front wall is the wall you look at)  
I doubt you will be lacking for power nor do I think you need esoteric cable to get fine results--I used Supra Rondo 4x4.0.

Hello All, the experience and added use-case scenarios will be passed along. Interesting placement variation so far with the different room sizes. Thanks.  

Have 1.7’s in a room slightly larger than your friends with a vaulted ceiling. I played around with positioning for about a month and landed on 32" from the front wall (measured from the tip of the foot closest to the wall). Any further and the bass dropped way off. Place tweeters to the outside. I would start by spacing the speakers 60% of the distance your friend is sitting away from them. This is stated in the Magnepan manual and I ended up pretty close to that after the month of playing around.