Very cool, that is way to do it if you can.
The biggest problem is making sure the stand rod is straight when making your own. The FSM says the level of slack in sizing is +/- .025mm. So the tool should be more accurate than that.
When I went to make my own, it ended up being the bracketry and armature that kept moving, even if ever so slightly, and giving me inaccurate readings. Those black hand tightening clamp type brackets... no fun.
Like this:
The is a solid bracket that locks into adjustment firmly and easily (hex keys). It also uses a digital gauge instead, that you can use to quickly calculate the needed shim size.
here is the instruction guide for the tool
http://www.rpsport.net/support...s.pdf
John