I found that my problem printing to page sizes smaller than 1 inch turned out to be the parameters of the printer driver. Many printer drivers only allow page sizes down to 1.0 inches.

If the page size you specified is outside of the parameters supported by the printer, then the print form will not appear in your list. Windows filters it out. This will vary by printer driver, but you can check the maximum page size range (for postscript...

I have the same issue in certain circumstances as well, however I am able to create most custom form sizes (very small...1.5" x 1.0", for example) and then select them in Word. In order for the printing to work properly, however, the page size in Word must match the page size in your custom form. The custom for will appear in the paper size list in Word. Since my page sizes are dynamic, I wrote code to make the printer form changes on the...