Hello Phil,
I am professional engineer.
Depending on what you are doing, usually one tap can do all.
If you need a long series tap, usually a normal length tap can have an extension attached to the end to increase the total length.
I have all these available,....and because you are a valued forum member i can loan to you free of charge.
Alternatively pop over sometime with what you need tapped and i can do this for you.
Anyway maybe give me a call to discuss further.