I am new to fly tying, and I have a few questions about some of the nymph patterns.

EZ Nymph
I have been tying the EZ Nymph pattern from the Beginning Fly Tying section by Al Campbell. The first couple them that I tied had too long of pheasant tail fibers. The fibers extend about 1 hook length past the bend of the hook.
My question is should I cut the fibers back to the appropriate length?
My instincts tell me that we want to be using the natural tips of the pheasant tail fibers and that we should try to keep them intact.


Pheasant Tail Nymph
With regards to the Pheasant Tail nymph pattern, would it be reasonable to substitute loosely dubbed rabbit dubbing for the peacock herl that makes up the Thorax?
What about the color of the Thorax? Would it be reasonable to substitue different colors on the thorax (Brown, olive, tan, ginger, etc...)?


Hare's Ear Nymph
Most of the recipe's that I have require dubbing from specific hare's mask parts. Would it be reasonable to substitute natural rabbit dubbing from one of the WAPSI dubbing dispenser kits?
What about other sources like wool yarn? I have some wool yarn bits from another project that are fairly coarse that would be a good color for this pattern.


Ribbing Wire
Do the standard ribbing wire materials corrode?
Would it be reasonable to use copper wire from an electric motor as ribing material?


Thank You