I’m planning to do a wavien style scratch build. I’m currently trying to decide on a lens and am considering three I found. Two are cheaper moulded lenses. One is a commonly found 78mm lens with a 50mm focal length. The other is a 100mm lens with a 80mm focal length. The third is a surplus precision ground coated 79mm plano convex lens with a 105mm focal length. Currently inclined to go with the 100mm but would like opinions. Since it’s a scratch build I can tailor it to the hemispherical reflector and lens I select.