yeah the total width in all listening positions across my seating area is 36 degrees (actually a hair under that) so 18 degrees from center to each of the left most and right most seating positions. for most of the MTM centers you are hard pressed to find anything that doesn't begin to have serious off axis issues beyond 10 degrees from center - 20 degrees total.A plot showing, say 25 degrees, is greater than +/- 18 degrees.
(I.e. You do not need to double the values as it is relative to being “off of the centerline”.)
vertically the center speaker is 7.6 degrees below my ear level but i do tilt the front speaker and use a laser pointer to angle up towards ear level to negate that. i have about ten inches of height space to work with for the center speaker but that is reduced when the speaker is angled.
ideally i'd love to be able to use a revel c208 but i just don't have the space for that. a c25 or a c205 would fit comfortably but i would prefer a little larger woofer in the 6 to 6.5" range. i have pondered just grabbing a kef q350, laying it on its side and calling it a day. the only real downside to that is to get the most out of a q350 you need equalization in the higher frequency region so it leaves me a bit apprehensive. ARC genesis will smooth that region but it will also color the sound of the speaker in doing it.