I plan to use 15W/40 mineral oil with ZDDP additive for the break-in , despite I have roller lifters ...
Check out the VALVOLINE VR1 Mineralic 20 W 50 it is realy a good oil. Other than that i´m using ZDDPLUS to bring up Zinc and phoshat level to above 2200 PPM ( VR1 original still has about 1400 PPM, which is 100% more than in most street legal fullsynt´s with about 500 - 700 ppm))
also it stays quite viscous in higher temperatures and therefore is not easy pressed and squished away.
Cam and Flat tappet lifters look like new on my car after 4500 km.