Well, um, I can't speak for your other machines, but we used to do that with the Mobile Maid with the bow-tie impeller since the hooks for the top rack were on the front and back of the tank leaving the spaces on the sides of the top rack open to lower a cookie sheet. And, with the flat sides of the tank, saucers and stuff that went in the rack at the side of the tank could be loaded right up against the cookie sheet or either part of the broiler pan when they were placed there. I can also do this with my KD2P and, with its 3 section-top rack, I can even leave out a section or 2 or 3 if I need more space for tall things to stand up in the bottom rack like 4 cookie sheets or other large items.
With modern chlorinated detergents, I am not surprised that things wash well in the YT or the other old machines. When we started giving friends that commercial chlorinated dishwasher detergent in the 50s, they said it was like getting a new dishwasher, the way the cleaning improved. I think it is a lot like using modern beefed-up HE detergents in older front loaders, not that we found faults with the cleaning of our tumbler machines; we did not have a reflectometer or whatever they called it.
Didn't you love those detergent cans with the spouts for both laundry and dishwashing products? No concern about air tight containers there.