You should have a big head start thanks to your previous experience.I would caution that a very large Z axis travel may be of limited value.Draw the motor you plan to use and include the longest feasible cutter.Then draw a line from the edge of the cutter and tangential to the motor body and this will give an idea of the steepest face that can be machined.It gets worse on the side of the motor that attaches to the Z axis.