Tudor / Rolex straps

[jmsjabb]

I have a 1974 7016 Tudor sub and I bought it with a 9315 diver extended strap. This is far too big, think 2 or 3 lugs, so will need professional alteration if I am to wear it.
I have had it authenticated but it isn't the correct strap for my watch.
What should I do?
I think the right strap is a 7206.

Now, do I sell the 9315 and find a 7206? What prices are we talking, for mine and the 7206?
Do I sell the 9315 and buy a generic strap or a later Rolex strap?

Opinions please!