when should oil be changed after breakin

Did this exact process, after cam break in. I did it because I was afraid I hurt something that I caught right after initial drive.

I didn't see any metal, eventually discovered that I didn't even hurt a journal, but what I did see in the oil was a lot of black pearl, lots of the parkerizing from the cam and other stuff in very fine granules. No break in lube up high at the cam or lifters, it all ended up broken down in the oil and filter.

After seeing that, I'm convinced that dropping it after cam break in is the way to go. I've heard of other people dropping it after 500 miles and have seen it successfully done on a couple of street cars, but I like the idea of changing it up immediately after.