John Cutler
A couple more thoughts.
Ensure you are confident that your choice of coupling will work for you before buying a large quantity. Buying a full complement of Kadees might come as a shock to the finances!
You might want to buy more than enough couplings for your immediate layout needs. Bear in mind that both Lincs and Dinghams were unavailable for some time. You cannot buy Yeovils or the Fleetwood Shawe coupling any more. There is a risk involved in buying a proprietary single-source coupling.