Robin,

The G-Claron 305mm 1:9 in Copal #1 shutter with speeds to 1/400th would certainly be a commendable choice with an image circle @ f22 of 381mm. Flange focal distance (bellows draw) at Infinity is 301.7mm, it weighs 460gms and uses 67mm filters.

But you might also investigate the Nikkor-M 300mm 1:9 with an image cirle of 325mm @ f22, great if your format is 4x5. For Infinity focus the Nikkor has a flange focal distance of 290mm. It is also in a Copal #1 shutter and takes 52mm filters. It weighs just 290gms!!

Having said all of that I use a 300mm 1:5.6mm Apo-Symmar which uses 105mm filters and weighs a ton. Perhaps i should heed my own advice.

Good luck ... WG