I have a job that is wanting me to frost some interior office windows but three of the 35 windows are 5' wide. They are wanting to frost the entire window (no design and no gap) but I am limited on types of film I can used due to the 5' sizing. My question is, is there a good technique or way to seam two pieces together. The three windows are 5' wide and 6 feet tall so the seam would be at about 8' (small 3' windows below). I haven't messed with to much frost full coverage but we do window tinting here so I was gonna attack it similar to that. Second question is do I use soap and water or do I use a particular solution that want leave any streakiness behind?