Mike, KB3EIA wrote:
"Are there any good references to the effects of shielding effectiveness
as related to shield coverage?"

Yes. As Richard Clark noted, it is related to penetration depth of the
materials and that is related to "skin effect".

The best exposition of skin effect in my opinion is given in
"Radio-Electronic Transmission Fundamentals", a text by B. Whitfield
Griffith,Jr.

Originally published in 1962, it`s return is a reprint by Noble
Publishing Corp., 630 Pinnacle Court, Norcross, GA 30071; tel
770-449-6774; fax 770-448-2839; orders@ noblepub.com; www.noblepub.com.

Original publisher was McGraw-Hill.

The new Second Edition is a 648-page hardcover book which was reviewed
in the "New Products" section of the Jan. 2001 QST on page 48.

Griffith graduated from MIT, was a licensed radio amateur, senior member
of the IRE, Texas Society of Professional Engineers, National Society of
Professional Engineers, and ARRL.

In the original edition, "Skin Effect" begins on page 232. "Radiation
and its Control" begins on page 243. You don`t need calculus to
understand Griffith, but calculus never hurt anybody.

The reprint is well worth the $75 asked in 2001. In fact, it would be
worth searching elsewhere if the 2nd edition is now out of print. This
book is outstanding! ISBN 1-884932-13-4: order number NP-34. You won`t
find clearer or more concise.

Best regards, Richard Harrison, KB5WZI