Keep in mind that different checks may have some of the fields in different places (I think). The routing and account numbers will always be in the same place, but you don’t want to print those. You just want to fill in the blanks in a pre-printed, blank check, right?
You can make this yourself. Get yourself a metric* scale, and measure all of the key points. Put your illustrating program in metric units, and do it by trial-and-error. Save your checks by printing on regular paper (you can hold a check up behind it and hold them up to a light to check alignment). If you don’t have a good illustration program** PowerPoint will work in a pinch. You can’t make it metric, though, unless you change the whole O.S. If, though, you type “mm” into the text boxes, they’ll be converted to English units automatically.
Metric is good because mm have more precision** than inches.
**An illustration program isn’t Photoshop; it’s a vector- or shape-based drawing program.
***Precision in the lay sense.