[RWebb]

thx - I'll just have at it then.

Seems like I can just set the router depth using the other

One thing is I'm not clear on what sort of errors (tolerances) are required... as usual - I've worked in all sort of tolerances - took classes as a machinist and cabinet maker and used to date a metrologist at hp - so there is a lot of variable variances floating around in my head...