Subtract one from that camp; From the time that I took machine shop in HS from a teacher that apprenticed at Mare Island Navy yard, and taught in the apprentice school, and was subsequently apprenticed in a large local shop, I never knew of any fellow machinist since that did the 29deg. thing. The only place that I hear about 29deg is on this forum; I am now going on 75 years ago, and can say that 30 degrees works just fine, with no incidence of steps on the backside of the thread. So far as feeding straight in, except for very fine pitches, it is not a good plan, as the chips coming from both sides of the cut interfere with each other at the center, and can cause finish problems. going straight in can cause problems with remembering dial readings.
As an aside, the Europeans have the custom of feeding straight in with the cross feed, but feeding in with the compound from right to left with each succeeding cut, this told me by a German guy in our shop, Karl Groneck.