IIRC, Kas Kastner recommended more like 1500-2000 rpm, and warned against going any higher even momentarily. The goal was specifically to let the cam lobes work harden and mate to the (new) lifters; rather than worrying about ring seating, etc.
This process would definitely be best using either a high zinc oil, or a zinc-bearing "break in" additive, IMO. Non-detergent oil does not belong in a car engine!
My feeling is that in general, it is far better not to mix different oil formulations. Motor oil blending is a complex topic, with research going on all the time; and additive packages are carefully compounded to work and play well together. For example, a low-zinc oil may have a calcium-based substitute for ZDDP (the zinc based "anti-wear" additive), that is not compatible with higher levels of ZDDP. I used to read some of the tribology (lubrication) journals, and one of the last ones I read had a research report about just that problem. The mixed additives performed worse than either one by itself.
But any Autozone or O'Reillys (do they still have Schuck's in AZ?) should have Valvoline VR1, which is a well-known brand with plenty of zinc (and what I use). If you watch their flyers, it goes on sale once or twice a year for about the same price as the cheap stuff normally sells for.