The metal yoke contacting with the metal box would transfer at least some heat to the metal...in a plastic box, there's not as much conduction. Effectively, I think it would make the heat sink a little bigger. Probably not enough to worry about.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013
I just did a little google hunt, found the installation instructions for lutron's multi-location dimmers. Look at the diagram for 3-way dim-from-either-location. Looks like a standard 3-way setup, to me...
...upload's not working, for some reason. I think the file's too big. Here's a link to the download page:
Master Plumber Mark:
there is nothing better than the
manly smell of WD 40 in the air
while banging away on brass with a chisel and hammer...
it smells like......victory......
do not hit your thumb...
Just so everyone's clear: I'm the POODLE in the picture ("french", get it?) The hot woman is my wife.