thing is i have a cossie breather already that has a few ports and a return to sump and atmosphere ( not the ggr type one but the more comon cylinder types you see)

seems like i can use that and be sorted, just use one outlet to feed the catchtank aswell and maybe block off the return to the sump perhaps (is returning to the sump a good idea and do you spit that much oil into a breather to notice a difference ?)