Hi Bill:
You might want to get a site survey done before drilling any holes in your soffit or eaves. I've seen customers prewire and predrill assuming the dish will be located at a certain spot but when the
installer shows up it turns out to be not the right spot, so.... it costs $50 or so for a site survey but its money well spent.
The switch is usually mounted right on the dish assembly itself - at least that's how I do it. There are 4 cables from the LNBs to the
multiswitch and then up to 4 cables from the switch down. So the hole you drill should allow up to 4 cables to pass through.
kat