I finally decided to make a vacuum formed polystyrene cover for the encoder
on the front of the big mill. Seems pretty straight forward. I've got my
first vacuum box finished except for the port to put the vacuum hose in. I
noticed a lot of the DIY guys make a hole for the smaller vacuum hose even
though they have a full size shop vac with the big hose. Is there some
reason for that? Seems to me that the larger port for the larger hose would
evacuate the box faster and form the plastic quicker before it cools. Am I
missing something obvious?

(I have some PETG on the way to play with in case I don't like the way
polystyrene forms or holds up)

If this goes well, I have all kinds of ideas for vacuum forming...