Thanks, I'd have to double check since I didn't buy the chassis (it came with the parts that I bought) but I'd guess it's 17x12x2. The height is going to be tight and clearly real estate is at a premium. The Electraprint iron isn't exactly small though.
I'm pretty sure that the grommet is part number 9311K139 and yes they are from McMaster Carr. If you search for Vibration Control Grommet you'll find a range of sizes and styles. I picked these on a recommendation from a friend who had used them in several projects.
One of these days I'll get back to chassis fab, but runny noses have been hurting my efficiency.
And of course, welcome to Head-case. There's a few other NH/New England folks around here although the DIY contingent is a little on the light side.