DIY Slim Phatty rack ears?

Hey y’all

I know the SP rack ears are only like $30, but say I was a cheapskate (and didn’t want to wait on mail order) and wanted to improvise my own. Would there be anything particularly wrong with rummaging around Home Depot until I found some suitable small L brackets for each corner screw on the slims? I am just now entering the world of racks, so tell me if I am missing something super obvious here.

From my experience (and Im speaking on a general basis here) its usually better to wait for the real deal rather than cutting corners. Other than that youre not missing anything obvious.