Paul, thank you it's super to see this registration, especially as Rd number 750112 wasn't on Great Glass or in the Blue Book, so we were a bit in the dark, but you are correct in that we should have suspected Clayton Meyers, and it's good to have that confirmation now.
As to comb tray, I guess it comes from the big trays we see on many sets being used to accommodate a hair brush, comb, clothes brush set - I recall having a set like that when I was a girl and my mother and my grannie had one too. Some of the continental sets don't have the big tray but have a narrower tray which is often referred to as a comb tray (as a comb would fit into it).
It's interesting that the Registration only shows 6 pieces, as there were various other bits in the Crane / Kranich pattern too:
Tray, pattern #8820, size 285 mm x 235 mm
Large lidded pot, pattern #8821
Small lidded pot, pattern #8822, size 80 mm diameter
Candlestick, pattern #8824, size 150 mm high
Ring holder, pattern #8825, size 95 mm diameter
Pin tray, pattern #8823, size 108 mm x 70 mm x 20 mm deep
Soap tray, pattern #9929 #9959
Pot, pattern #9927
Atomiser, pattern #9928
Perfume bottle, pattern #9930
Comb tray or jardinière, pattern #9931 #9960, size H 6.5 cm, B 8.5 cm, L 22.5 cm
What your lookup does confirm though, is that the RD no relates to the Inwald original design and not just to the Leroc added enamel decoration, and that is good to be able to pin down, so thank you again.