Kelsey Hayes disk brake conversion question

This is awesome info. Thank you. I bought all of what was shown for $100. Can I buy the items that are missing from an auto parts store or are there some of the items which have to be found from a donor car? I have a new dual mastercylinder. Will see if I'll need the proportioning valve. As long as I know what I need, will purchase this winter. Sure like the idea odlf the brake upgrade.