Oil Pickup Clearance, touch the pan, or no?

If you're talking about the factory style pickup there's no advantage to having a clearance under it, even with the pickup contacting the pan the channel that feeds the opening is larger than the opening so there is no restriction.

Aftermarket pickups like the Milodon must have clearance.

Years ago one of my friends believed that the pickup shouldn't touch the pan and hot bent it to get about 1/4" of clearance. About three years after this at the top of third gear, the pickup failed at the threaded end and he lost all oil pressure. Oh yeah, it was a '66 Hemi Coronet. IIRC there was just someone on Moparts that had the same thing happen, a crack at the pickup threads with the accompanying loss of oil pressure.

Without the pickup touching the pan it apparently can get into a resonance. This leads to metal fatigue at the threaded end with the eventual cracking failure. No, I'll continue putting BB's together with the pickup touching the pan.

...MAYbe this happens ONLY in ND ? ...

Absolutely not!! It should never touch the pan, UNLESS the pickup is the OEM syle mentioned above.
Two reasons why not: Dent the oil pan at the pickup, restricted flow of oil in pump and motor. Two, break something inside the motor, the oil flow is again, restricted at the pickup.

and a spacer would take of the resonance problem possibly causing a crack on down the line