I have designed my own diplexer LPF boards for my 600W EB-104 amp and I strickly used the Sabin design & component values for my boards. Here's a picture:http://janswerks.com/n8cbx/jans_filters_2.jpg
I am using only three bands at a time, because I'm on the lower HF bands (160/80/40), but if I wanted to go higher, I designed it so the LPF just plugs into a motherboard.
Here's a picture of a LPF & motherboard mock-up:http://janswerks.com/n8cbx/jans_filters_1.jpg
The motherboard has a general utility purpose that will serve the three LPFs, 2ea SWR/power bridges, band relay switching, 10db exciter attenuator and RX/TX relays.
I looked at WB6DHW LPF design and he is using a higher order filter, which may or may not be necessary, I don't know. Also, he is using some larger toroid cores than what I'm using. I used T130 cores which I think will be okay for legal power levels.