Engine break-in oil questions

I have always used 30wt break-in oil. After checking oil posts here and other sources, I have read about the change to oil and warnings to owners with engines with flat tappet cams. I looked at Royal Purple break-in oil and discovered it is only in a 10w30 weight. Would this be a problem. How many miles are recommended before changing the break-in oil. Thank you in advance for any good input.

 

Now that Kendall had it’s Zinc removed to preserve catalytic converters, Brad Penn oil http://www.bradpennracing.com/ has become very popular with it’s high ZDDP content. I know a few vintage cars that made the switch to Brad Penn. Also, I’ve heard of Joe Gibbs break-in oil http://www.joegibbsracingoil.com/ but haven’t talked with anyone who has 1st hand experience with it.

I favor using a generous amount of Red Line assembly lube, Brad Penn 20W-50 and changing the oil and filter after a few miles up hills in as high a gear as I can pull cleanly.