oil ring break in.

Well i got my rebuilt 360 broke in the outher day, but when are the rings broke in, the 360 has had 2 fire ups ran 20 minutes booth times,no isues, sweet.my engine builder says to get some 10 w30 royal purple synthetic, is it too soon to run synthetic, i know we want tones of Zinc, myself i like JOE GIBBS driven, any thoughts, crank is all stantered bearings.thanks gents.