I have always had challenges creating symmetrical corners from border punches. Part of the challenge is that you are limited by the spacing of the pattern so only a few sizes can be created. Another challenge is that spacing the punches so the corners appear to flow versus some catywomp shape can be nearly impossible. I decided to take up the challenge with the Stampin' Up! Eyelet Border punch. Here's how it's done. Click on the pics to enlarge for detail.

Cut a piece of vellum paper larger than the single punch created by the Eyelet Border punch. I used a quarter sheet piece. Punch a single punch in the center of one side and set aside. This tool will be used in the future as your positioning template.

Place the edge of your card stock just to the left of a center dot visible on the left side of the punch. Punch. Matching the pattern on the punch base, complete the edge.

Turn the paper a corner turn to the left and flip top to bottom so that the original upper left corner of the card stock is again the upper left corner. Place the straight edge against the punch guide.

Position the card stock so that the hole indicated matches the appropriate dot on the punch base and punch.
Matching the pattern on the punch base, complete the edge.
TIP: I always complete the punched corner as my second punch.

The next step uses the vellum template you created earlier. Lay the template on the card stock as shown matching a low left hole on the template with a low right hole on the card stock. Through the vellum you will see the corner you will be creating.
Mark the card stock with a pencil. Evenly cut the card stock with a paper trimmer.
Repeat steps 4 - 8 until all four edges are completed. In the demo I started with a 5.5"x4.25" piece of card stock. The finished product measured approximately 4.5"x3.25" PRACTICE MAKES PERFECT!!!