One possible vacuum chamber solution for the Gyro is to use long tubes for the Gyro arms and then to have a small chamber with ports at each corner.
I looked a little at using stock MDC vacuum parts for this; its not out of the question.
For the tubes, we could use something like their NW50 Kwik-Flange nipple. It has an OD of 2" and a length of 6.5". Its $63.
For the corners, we can use one of their '5-way crosses' like the 406002. Its basically 5 flanges welded onto a shell. Depending on the size its ~$250 ea.
I would prefer to get one long tube for each arm, rather than stick a bunch of short ones together, so I'll get a quote from MDC on a custom job.
Uncoated quartz viewports are ~$250 ea. I expect that we will want AR coated and angled viewports. Maybe $400 ea then.
So the total cost, without pumps would be ~5k$.