RE: primary taps

["Ted Rosenberg" <Ted.Rosenberg-at-radioshack-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Would anyone want to offer their observations on the following:
How small a slice of a Primary turn results in the best tweak of the coil?
Most report "my tap is at X and 1/2 turns." How about X and 1/4 or 1/8 or
1/16?
How exact?
I think from the posts I've checked that plus/minus a half turn is usually
all that's needed.

Thanks in advance.

Ted R.

And , yes...I am up to constructing the primary...can't wait to finish.
It'll be a year this November.