In message , JB
writes
http://www.arrl.org/notes/hbk-templates/stepatt.pdf
This is the one I based mine on. Fewer sections. The Slide switches are
superior because of lower inductance and the bulkheads help with
isolation.
I found there was another version in the TIS section:
http://www.arrl.org/tis/info/pdf/9506033.pdf

As the pictures show, there is screening between the switches (even
though it's a bit skimpy on the second unit). Even in the first, for the
ultimate in isolation, it would be even better if there was an RF gasket
on the inside of the top cover which, when screwed down, makes contact
with the tops of all the screens, and makes each switch compartment
virtually watertight.

Tin plated solder wick

Many CATV modules use a gasket made from the equivalent of a sheet of
spongy foam rubber/plastic backed with BacoFoil.
--
Ian