The end vise will have both jaws made out of 1-1/2" thick oak. The front vise has its moving jaw made of 1-1/2" oak, but uses the edge of the bench as its stationary jaw. So while for the end vise, if we mount it lower, we can make both the jaws deeper to compensate, for the front vise we cannot, so we want it mounted as close to the edge of the bench as possible.
Clamp the inner jaw of the end vise in position, leaving a little bit to trim off later, and then use the dowel and dowel center trick through the screw and guiide rod holes of the vise base plate to mark the position of the screw and guide rod holes in the jaw. Remove the jaw and drill 1-1/8" holes in the marked positions. I used the drill guide for most of the holes, and drilled freehand for the last bit. When you're starting a spade bit in a deep hole like this, start the drill very slowly, and the bit will move the drill into a perpendicular position. Start it too fast and the bit will bind and you'll damage the sides of the hole.