I just follow Brooks instructions, Profhide on the top surface and on the underside.

Other treatments may block the pores or soften the leather too much.
I never had a problem breaking mine in, just do it very gradually over a few weeks. Dont expect to ride 50 miles on a brand new Brooks; I limited my use to a few miles around town, until I could feel it shaping up. I just dont understand the need for extreme treatment of a saddle.