With any combination of zoom/shift settings, did you manage to get the calibration page to print out perfectly *centered* (horizontally centered, that is?) That's the factor that influences how accurately the front/back line up. For zoom 3 / shift 7, what browser / OS were you using?

If anyone reading this thread is scratching their heads, this is what we're talking about:



So far I've had the best success with Safari, pretty good with Firefox & IE, possibly some problems with Chrome.


Not yet. I'll think about that some, like a "master zoom" function. However the resulting wallets wouldn't size properly for the tamper-evident tape I sourced -- so you'd be obligated to use regular tape.