Ok, he was using "thin emulsion" incorrectly, but that wasn't anything unusual for Fred. Tech Pan may have been "even thinner" but all modern films are thin emulsion, see Ansel Adams' The Negative for numerous references to negs shot "on the old thick emulsion" film and such.

What he meant was an ultra-soft working developer. Films like Tech Pan were originally meant for copying line art, very high contrast. The grain size is much more even than in conventional films, and this tends to result in a given light level either affecting all the grains or none of the grains = very high contrast, not a problem for line art and in fact wanted, but not what you want for pictorial applications. I recall the article in the old Pop Photo in, I believe, the late 70s when someone finally worked out a developer that worked well for Tech Pan at normal contrast, after many had tried. It caught on enough that Kodak came out with their own Tech Pan developer.

Pan F really isn't anything like those films. It's more like old Kodak Panatomic-X. I think it tends to be contrastier but I haven't used either in more than 15 years and didn't use much back then. I do have a couple of rolls of newly acquired 120 Pan F in the fridge now to try out.