Peter, I cannot comment on how effectively they work with some 5 speed freewheels, but I can have one now in use which seems to function fine with an old French made Atom 5-speed.
I will also offer here what is presented in a Cyclo Benelux Catalogue dated 1962 (and I suspect that specific model did not change significantly over the years):
"Available in four types: 3-speed for 1/2" x 1/8" chain, 4-speed for 1/2" x 1/8" chain or 1/2" x 3/32" chain and 5-speed for 1/2" x 3/32" chain. Sprocket range: 13T. - 24T. With double chainwheel overall range 15T. difference."
The Mark 7 model CB73 was for the first two options and model CB74 would be used for the last two.
Two words of caution:
1.) The 13 and 24 tooth sprockets mentioned above were the largest and smallest allowed. However, the recommended difference between cogs was only 10t. So, 13-23 or 14-24 would be your maximum range options.
2.) What they mean by "overall range 15t difference" would indeed mean a difference between chainrings of only 5 teeth... which is of course a very uncommon spread to our modern eyes which are far more accustomed to at least 10t [42x52] or, more recently, 14t [39x53] between chainrings.
PS: The 1962 US Retail List price for the Mark 7 was only $7.14 ~ Good Old Days!
Bob Hanson, Albuquerque, New Mexico, USA