Pegboard Jig

This is NOT my design. I found this on Instructables, it was created by a user named Paige Russel. It was uploaded there for users to download for free and either print themselves or have an online printing service print for them. I have found one thing that does need to be altered in this design, but I do not know how to do it. The peg wings on the outside edges of the jig need to have the holes on the underside increased to 1/4 inch or .25 inches in order for standard 1/4 inch dowel pins to be used. There are 4 pegs included in the STL that get installed into those holes, that are not a very good fit, and I have actually destroyed mine. I had an online printing service make this for me as I do not yet own a printer, I am still saving up my money to buy one. I am hoping that someone out there can make the alterations to this that I am looking for. My only other option would be to bore out the holes with a 1/4 inch drill bit, but I am afraid that I will either break the jig itself while drilling, or not get the drill bit properly centered. Either mistake would surely render my jig useless.

If you do edit this so the holes I referred to earlier are 1/4 inch, please post a link here in the comment section. Thanks in advance.

If you decide to make this jig, you will also need a bag of these nylon spacers.
https://www.mcmaster.com/94638a259

Here is a link to the original design along with full instructions on how to use it to make your own pegboard using any 1/4 inch thick plywood, MDF, or other material.

https://www.instructables.com/id/Make-Custom-Pegboard-3D-Jig-File-Included/