I don't know why I did think of this years ago.  If you need to remove the flex plate, fly wheel, or front crank damper with the engine out it's a little difficult when you are by your self. 

 

A couple of engine changes ago, I found an easy solution, the double box end wrench, I'm using my 13mm - 15mm.  Simply put a 12mm bolt into the flywheel through one end of the wrench and then turn the flywheel until the other end will drop over the long engine stud. 

 

Works going on or off to lock up the crank.

Same idea as the factory flywheel-stay tool.  I made one out of flat bar stock with two holes drilled in either end.  One end slips over the engine stud, the other hole is captured by a clutch bolt in the flywheel.