David,
That's correct; otherwise, the tinsel body sometimes pushes the tail down below the horizontal, which I don't want.
Squirrel can be very slippery. One thing I sometimes do is dose the butts with some Sally after the first couple wraps, then really lean into the thread as I continue to secure the wing; didn't have to here because I was keeping things sparse.
The stuff I got was very inexpensive; check places like craft stores, Dollar stores, etc. Buy it in a fly shop (tinsel this wide would be equivalent to magnum saltwater Flashabou) and you'll measure off every piece before you even think about cutting it
Regards,
Scott