Sorry meant to say with the 6.5 L tank you can easily get two of the four CB750 carb bodies in there. I generally put them in as pairs and work on the clean pair whilst the other air is cleaning.
Also, if you have stuck float pins / stubborn to remove parts it's worth soaking the while carb unit at 60-70 deg for 10-15 mins, then quickly remove and try again to freee up / remove the parts that were stuck.
I've brought back quote a few sets of carbs from the grave that looked uneconomical to refurbish / clean.