Bidding on clad casement window replacement.

Any other window I have replaced has had trim around it. I was able to remove the trim, install the replacement using the flanges and flash.

In this case, there is no trim. On part of the window, brick runs right to the window. On the rest- steel board and batten siding and j mold running right to the window with old masonite vertical siding underneath, window flange and then asphalt board.

I have already replaced a window in the same house were there wasn’t any brick by unzipping the siding and cutting strips of masonite siding out.

My question is how to deal with the part of the window trapped by the brick?

I can cut the window flange on the old window to get it out and install the new one without the flange. I am just not wild about relying on caulk alone to seal between the window and the brick.

The largest of these windows it 73wide by 63 tall.

Any advice?