Clint
WACOs are notoriously difficult, and using a designation system which could make any full grown man weep with frustration....
Thanks to the rear window and balanced rudder, which was introduced in 1935 on the YKC-S and later the YOC and CUC, we have two aircraft to chose from
1406 ex ZS-AFU (model CUC)
1419 ex ZS-AFH (model YOC)
There is also a third alternative left to consider
1409 ex ZS-AMF (model ZKS-5 according to Brent but a ZKS-7 according to WACO documents)
However the few photos I have seen of this latter model all have a different engine cowling.
Model CUC used a Wright 250hp engine
Model YOC used a Jacobs engine
Unfortunately I cannot see any other difference between these two models, so that is far as I can go....
Cheers
Stig