Axiom speakers--and the M22s--are designed to sound their best unencumbered by "adjacent surfaces" (the surrounding cabinetry) and will be the least colored when you hear them on stands (the exception being some of our in-cabinet models, whose frequency response is tailored to compensate for built-in applications).
If you must put the M22s into built-in cabinetry, try keeping the front edge of the speakers protruding a half-inch from the edge of the cabinet to minimize diffraction effects. The space behind the speakers will be OK, but try auditioning them on an open shelf before you put them into cabinet cubby-holes. You may much prefer the neutral sound quality when the M22s are in the open or at least on an open bookshelf.
What about placement in front of a window or curtain?
The plan is to replace my current speakers which are
slightly toed in and 12" from a blackout curtain.