I use the Infinity for flattening my CNC table, works perfectly for me.
But if you dont have an OF2200 and only have a smaller router you better use the smaller bits, that 1 1/2" bit takes off a ton of material and creates massive dust. Dust collection is a must if you go router.
The router set up for this can get tricky if you want a perfect board in the end.. I suggest using a friend or a local shops drum sander, NOT planer(thicknesser). Place the board in the sander hump side up and take it down a bit on that side first. Then after it looks good flip it to do the other side with a final pass.