The oil film I am talking about is the oil retained between the bearing and the journal - the oil in the sump is for cooling - the only reason you need pressure above a certain level is to assure sufficient flow to all parts of the engine. The rotation of the journal creates the wedge I am describing; the journal actually rotates slight off center in the bearing shell and acts very similar to a pump with no vanes.
The load carrying ability of the oil is based on viscosity and surface tension more than on oil pressure - if you think about it there is no way that 60 psi of oil pressure can support the journal of the shaft from contacting the bearing shell if you were relying on oil pressure alone to carry the developed loads from the gas forces applied to the piston, the con rod, and onto the crank...
A standard rod bearing in a multifuel maybe has 2 square inches of area in contact with the crank pin - I am pretty sure the firing impulse creates more than 120lbs of load
And worse yet in scavenge the piston has no opposing gas forces when it turns around at the top of the exhaust stroke - the inertia loading is huge at this point... It only gets worse with RPM and is the reason for many rod bolt failures.
The load carrying ability of the oil is affected very minimally by pressure - thermal break down from low exchange volumes and high heat will cause the oil film to fail quickly - excessive clearance will create similar problems...
HTH
Matt