Break-in oil ?

  I've been using Shell Rotella T4-15/40 but a "little voice in my head" is suggesting this is too heavy for the break-in.  I'm favoring  a 10W-30. 
Would appreciate some opinions for this initial fill of oil. 
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Shell Rotella T4 has ZDDP (Zinc Phosphorous ) in it and that's exactly what a good break in oil should have. Grade wise I would use 10w-40 all the time. I like a thinner oil on start up and a heavier weight when hot. For break in 10W-30 would be preferred and just don't push it for long periods during break in. My idea of break in is the first 500 miles. then change the oil and start pushing it