Need a 420mm barrel lens to fit a 4in board

Hi all,

I'm looking for a 420mm to use on my Gowland, and wanted to knoow which of the readily available process lenses, ronar, artar and nikkor will fit on a small 4inch board. Also, if anyone has experience using a Gowland at full extension, let me know how you've fared.

They all should. However, if you can find a 420mm Schneider Repro Claron, it will probably be a direct fit into a Compound #3.

Steve