Gentlemen,
I wish I was clever enough to take a photo of my Valiant CoG slide rule to show you all the u/w bomb loading details. Can do the photos but can't do the complicated stuff to get it on your screens! I think they were also intended to hold photo flashes too as certain positions were annotated as "applicable to P.R aircraft only." The only photo flashes I ever flew with were in a separate compartment behind what would have been the bomb bay in a normal bomber.
RATOG was mounted externally on the fuselage. As a very young copilot I flew a RATOG trial with the BCDU at Wittering. It was very impressive but they then had to be dropped on a subsequent run over the field. Not very successful as the parachutes failed to deploy. If my memory serves a max weight Valiant 184000lbs? got airborne in less than 1000 ft. The captain on one flight was a Sqn Ldr Gibson and on another it was Flt Lt Hogg. The aircraft were ?400 and ?872. Keen historians can probably fill in the details. I also flew on a Water Meth trial but I cannot remember the details.