Thien "Lid" Components Question

[leslyons]

Hi Everyone. I'm very new to this forum, and this MAY have been answered in a previous thread, and I'm just too new and ignorant to find it! I've made a lid for my metal trash can from 3/4" plywood, and am making the Thien baffle from 1/2" plywood.

I have two questions:
1. For 4" piping, how far down (in inches) from the underside of the top lid should the baffle be placed? Should it be fitted immediately under the elbow, so the elbow essentially "rests" on the baffle, or should it be deeper?
2. For the center 4" "output" connector on the lid, is it OK to use a Port (similar to the Rockler Dust Rite Combo Port # 28666) that mounts to the top side but does not extend down past the under side of the lid into the can, or does that mess up the airflow/collection? I hope this is making sense. With a 4" hose connector, it would connect on the top of the lid and extend down about 2" or so inside the can. With a "port" like you mount on a tool, it flush mounts on the top and then there is just the 4" hole that goes through the top - nothing extends into the can in the center portion.
Thanks very much for the help!