Here's a method I used to mount a small/medium sized metal working vise (45#) to a 1 3/4" thick maple butcher block bench. This methodology could also work well on an MFT, just be careful of those spindly legs. [eek]
The vise is a Starrett 015 with 5" wide jaws and a 7" throat depth. It's mounted to a piece of 3/4" ply with 3 each, 3/8-16 button head cap screws that are screwed into stainless t-nuts. This vise/plywood assembly is then mounted to the maple top with 3 machined aluminum T-dogs. The small diameter of the dogs run around 19.8mm, so they fit fairly snug in the 20mm diameter holes. This way they can be inserted or withdrawn by hand but with no side-to-side play.
The dog head diameter is 1 1/4" X 1/2" thick. The opposite end has a 3/8-16 tapped hole in the center that will receive Woodpeckers hand knobs that fit 3/8" hex bolts. The dogs are machined from either 6061 or T6511...can't remember which.
Two of the dogs attach to the bench top from underneath, while the third is attached from the top with the hand knob below the maple top. I would have preferred that all three were tightened from the top to make them easy to get at, however, I wanted to keep the plywood profile as small as possible so I had to compromise.
I made this conversion about 5-6 years ago and have mounted and worked on cast iron pipe, copper pipe, alum & steel angle, motorcycle transmissions and 80/20 extrusions in the vise along with 2X material/studs and LSL beams. I've had no issues. [smile]