I had the same problem when I assembled mine. I just took several photocopies of the board, and adhered with tape to the top of the amplifier enclosure. Then I could mark the holes and drill them.

I also bought a metal punch but ended up using conical drills of several sizes - that went faster and cleaner than the punch. It was my first project involving metal work!

@ccat707 Could you post a picture or two of your board mounted amp ? I'm getting to the part where I'm ready to assemble and test and thought I would mount to a board first and then transfer to a chassis. I'm curious how you set yours up. Thanks in advance !

Thanks for sharing that picture !  Your build looks nice. How does it sound ?  I like the way you attached the power cord iec connector to your board. I’ll get to install my transformers in two weeks and power it up. I like the simplicity of board mounting, but am also a bit worried about the high voltage.

Thanks! I did print via the method you suggested. A little playing around with print sizing, but got it to scale. Next time all plan ahead!
Thanks again!