Just change the vector file to what you want. If you have specific measurements to meet, just change them in the vector file, or ask someone to do it for you.
That's a big reason we made all of these things into vector files, so users could change to suit. I don't think we made any claims about these files being totally accurate like a repro (though we certainly try) but if you have the original CPO and you are trying to match it, I would suggest creating a print off of your own printer, then paste it together, and drop it on the CPO to test the sizing. That would work much better than worrying about it.