Hello,
Thanks in advance for the ideas.

We are replacing all of the windows in our gut rehab of an 1880 brick home in Northern Michigan.
1/2″ is the greatest measurement any of the window frames are off square.

Do we:
1. Replace with flanged windows, build four sided pressure treated buck, using sealing tapes, spray foam and then finishing over the exterior perimeter gaps / build up with aluminum and caulk bead sealing window to brick surround.

2. Replace with Non-Flanged and fasten through window frame directly to brick with strapping and a (slightly) larger bead of caulk sealing window to brick surround.

Option 1 will provide more barriers between exterior and interior to prevent water and air infiltration but will reduce glazing (relatively) significantly.

Option 2 will increase glazing (relatively) significantly but will reduce our exterior barrier to a single caulk bead.

Thoughts?
Thanks very much.
SB