I have built over 20 fish houses
By far the best windows are the jeld wen vinyl windows. Get them with the j channel built in and cut off the nailing flange the j-channel flange laps the window opening and your window only sticks out 1/4″ .menards stocks these in white I think a 24×32 window cost under$100.00 can order different colors but takes 3 to 4 weeks