I used the mechanicalkeyboards.com Phantom plate w/ lfkeyboards.com TKL PCB.
To fit the plate securely I just added a bunch of drawer liner under the PCB, so when you put the bottom plate on, it pushes the plate against the top case. Not perfect, but works pretty well I think. I can take some pictures later to show the gap that you need to fill to get the 2nd set of screws to fit. You could use a thin piece of metal/wood/acrylic that goes between the plate and the bottom screws. The two top screws fit this plate fine, just the bottom has a gap because it was designed for Filco plate/PCB
A second note about this PCB/Plate combo is the screw-holes on the LFK PCB are not large enough for the screws provided. So you need to install them onto the plate first before you start installing switches. I used some more scotch tape to hold the screw in-place while I went to solder. Alternatively you could just find some other screws that have a slightly smaller radius (this only applies to this LFK PCB).
So aside from the rubber feet, the next part of polish/improvement is lightpipes for the LEDs, the lfkeyboard PCB has RGB SMD LEDs for the two indicators, which is great, you can customize the colors, etc. But because they're SMD, the light isn't very focused. I used some scotch tape to diffuse the LED a bit. So now I'm also looking at getting some lightpipes from mouser or a similar place.
It also turns out my plate was bent a little bit so I needed to add extra padding to push the right half of the plate up against the top plate. Not sure if I bent it while soldering/installing, or if it was bent before. I'll check my other two plates later. Great part about this plate though is it supports Alps + MX (Just like the PCB) and if you're using MX, you also get switch-top opening as well.
I don't really want to take this one apart again just yet, the bottom plate is actually a really tight fit and it becomes a problem to remove it. Even if you unscrew all 8 screws, it's stuck in there with tension and you have nothing to access it with. I used a screw-driver through the top of my PCB (through another layout's switch cut-out) to push the bottom plate out. I knew because of the drawer liner all at the bottom.I wouldn't damage the bottom plate. But I have 2 more plates and 2 more cases, so I can take some better pictures to show the issue.