The points for 1936-60 are set at .022". The points setting was changed to .020 in 1961, which is called out in the '59-69 factory service manual (for the dual ignition) and the changed back to .022, when then single points circuit breaker started being used again. [Note: Chris Haynes has information that reveals the rigid Pan service manual was an enthusiast compiled publication. That being, the author used carry-over information from the Knuckle factory service manual and factory Shop Dope bulletins. Still the points are set to .022"]
It's the only disagreement I've had with Stett over Vol. 2. His take is, "I'm here in the trenches working on motorcycles day in and day out. We set the points at 0.020".
So, I let it go. I think we have the points setting listed as .020 - .022" in Vol. 2, to keep us both happy. But, I'm telling you what I know to be true. The points for 1936-1960 are set to 0.022". Go out and set yours both ways and run it. You'll have more throttle snap at 0.022" and with the timing mark set just to where the mark is visable at the back edge of the hole. This info is for 61 & 74 cu. in.
They did make a '58 service manual...only it's called the '59 to 69 service manual

The only thing that was different about 1958 were the tank emblems and the plastic front bumper tip. The Panhead motor was perfected in 1958 with the larger diameter and increased bearing surface side oiling pinion shaft.
IMO, 1959 was the last year for work-on-it-yourself Harley-Davidson. They started on a
git-modern race with other manufacturers, beginning with the aluminum fork cowling and dual points.
You might want to buy a "used" copy of our book. It deals with Pan cowboying, and happens that it's roots are in Houston-Galveston. Galveston was where the first set of
FHP Knuckle heads were sold and shipped by
San Diego Harley-Davidson, to
Reg Loudermilk (west island) to be exact, via referral from
Kick-Start M/C Parts, Inc.