Might also depend on how you are scroggin. Are you bending the stems under the screen or just using the screen as support/level-indicator? Then, as mentioned, how long are you going to need to 'fill in' the screen, or will you have numbers to 'fill' the screen from the start? How much stretch and how deep the penetration of the light (or the available 'working distance' from the light...etc. I don't know if you can get a pat answer to the question, but we can hit you with situations to consider...:damnhippie: