Sources of materials

[np01]

Hi

Bought the "Flies of John Goddard" book a few weeks ago (?7.00 from amazon - looks like new ). Was flicking through it last night and was keen to tie up a few of his patterns. In one of his patters (JG emerger I think?) he recommends blonde fly fur as a shuck material and grey calf's tail as a winging material - has anybody any view on how genuinely essential these are, and if they are, then where might I find supplies of them?? I've got some white calf's tail and I thought I might simply use that for both the shuck and the wings?? Perhaps this attention to detail is what separates the really great fishermen from us also-rans??

Thanks in advance for any help

Regards

Nick