GUEST,Geordie - Metal strings are easy to get hold of.
Fewer people stock nylon, but there are a few about. It may depend where you live. If you are UK, The Music Room at Cleckheaton sell sets. I expect Eagle Music near Huddersfield will also. Both sell online.
You say you have just finished making, then ask about tuning pegs. What sort of information do you need to know?
Do you mean that you have not bought tuning pegs yet?
Are you saying you still have to shape the head and want to know dimensions?
There is a lot of expertise on Mudcat, but it is easier to answer a specific question rather than guess what someone might possibly already know.
Quack!
Geoff the Duck.