Didn't notice this in the post so far, but if you're making your own table, consider making it with two layers of 3/4 material. Top of very flat baltic birch ply, underneath a layer of MDF. Carefully glue the two layers together. Glue a layer of laminate on top. Cut out the rough shape of the opening about half an inch smaller on each of the four sides, than the size of the plate. Place the plate on the blank table and mark the outline then use a half inch spacer to mark the inside cut line. This allows for the 1/2 inch rabbit that will hold the router up.
Next, lay the plate back into the outline and snug some straight edged boards up agains the four sides of the plate and clamp them down very tightly. Give yourself a little wiggle room by placing playing cards between the plate edge and boards. Push the plate out, and with a hand held router and a top bearing trim bit set to cut a rabbit slightly deeper than the thickness of the plate, cut a rabbit the size of the plate using the four boards as your template. Some companies will sell you a template for their plate. BTW, get aluminum as Mike recommends.
Drill holes in the rabbit smaller than the coarse thread leveling screws you will pas. through them. This will take up the slight gap and allow you to set the plate level with the table top. BTW, if you are not excited about gluing up 3 layers of different material, you could just buy a short section of assembled, new laminate and attach a layer of MDF or Baltic Birch ply to strengthen the top.
You can buy leveling screws on Amazon or a woodworking store.
At some point in the future, you may wish to install a router lift so you can adjust height from above the table. Instead, consider buying a Triton routher that has a lift already installed. The router is actually cheaper than most separate lifts.
Before you decide to install any kind of miter track, I suggest you watch some of the YouTube videos by Marc Sommerfeld, whose technique (and table plan and parts) is pretty much flawless, will affect how you decide on your final build. There are many things he does on the table that will really make you more productive with your own table.
Hope this doesn't put you off on your table, it makes routing more precise and safer than trying to do things freehand. If I can figure out how to do something on the table rather than freehand, on the table it goes.