Hi Stig,
Many thanks for your efforts. At least you've narrowed it down to two options and alas I have to agree with you, its not easy to tell the difference between the CUC or YOC. I guess realistically a deinitive id requires a view of the same machine showing the serial, or at least a photo of the machine showing the same livery but with the type designation given.Strangely enough, or not I haven't found any images of SAAF Wacos on the net. Hopefully ebay will provide at some future date.
With regard to the WACO designations, I found the explanations on Aerofiles very helpful when creating a list of the various WACO aircraft used by the different belligerents in WW.II. a few years back. at:
http://aerofiles.com/wacodata.html
Regards,
Clint