[time-nuts] Where to get Winchester connections for Efratom FRK?

[swingbyte]

Hi all,
Now that I have my FRK working I have to find a connection for it.  I 
believe it is a winchester 20p and I have not been able to find one in 
Australia yet.  Is it worth while looking or should I just replace it 
with something else or even solder leads to it!
As an aside, what resolution counter is needed to calibrate the FRK?  Hp 
5328? HP 5370?

Thanks
Tim