It is theoretically possible to use a blank punch card of any gauge because the framed area around all of them is the same width, 108mm. The holes that are punched have the same physical distance as the needles of that gauge machine. That's why the repeats are 12 x 9mm, 18 x 6mm, 24 x 4.5mm, and 30 x 3.6mm which all multiply to 108mm. I didn't know that for the longest time. The distance between rows is the same and so are the holes at the sides.
24-stitch cards are probably the least expensive and easy to find these days, that's what I used to make punch cards for my MK70. I also used the free graph paper program here:
http://download.cnet.com/Graph-Paper-Printer/3000-2064_4-10635500.html . It's a small program and works from my external hard drive. I used the settings in the picture below.
I marked the pattern on the paper with a circle in each appropriate square as well as two rows of circles above and below the beginning and end and used a fairly thick, pointed needle to make the guide hole in each circle. Each square has a cross so it is easy to find the center. I cut the paper around the outlines and taped it to the blank card, matching the edges and rows. I punched the holes through both paper and card with the card puncher, then removed the paper. Or one could tape the paper with the pattern on the card right away, punch the guide holes first and then punch the actual holes with the puncher.
It may be possible to punch a separate section of card with maybe four to six rows of holes and use it to join the beginning and end of any card with card snaps so one wouldn't have to punch the four rows each time? Haven't tried it though. The card worked on my machine without errors. More work than the real thing but at least the holes at the sides are already there.