Middle Atlantic UCP frame kit

Anyone here got any experience with these frame kits?

http://www.middleatlantic.com/products/accessories/connector-panels/ucp-series-modular-panel-system/fk2.aspx#compatible

In particular, I need to find replacements for the countersunk flathead screws which hold the 5 panels onto the frame. I can see them on the PDF for the kit on the Middle Atlantic website, but I can't see any mention of the thread dimensions/screw length.

http://cfgbridge.middleatlantic.com/api/Document/InstructionSheets/I-1600.PDF

Any help would be amazing!

6-32  and about a 1/4" long.

These should work:
https://www.fastenal.com/web/products/details/0144939

And at $0.0083 per, price is right.