One way to address the issue of the DOF causing oil pressure drop to the cam shaft bearings would be to install an in-line,adjustable oil pressure relief valve in the DOF line. Yes, this a clumsy way of doing it so I hope it will encourage others to contribute more elegant solutions. The Peterson 09-0160 is -10 AN so requires adapters for the smaller DOF line.Or a whole new line.
Peterson Fluid Systems 09-0160, Peterson Fluid Systems Remote Relief Valves | Peterson Fluid Systems
The flow in the DOF is very small so this may be unnecessary?Pedro claims only a 1/2 psi pressure drop.
The roller bearing thrust issue:
If thrust is the issue, just use thrust a washer on each side of the bearing ? Nope ! It will be too thick for the 6204 single bearing space. Unless someone has a trick part number for a much thinner single row 6204 equivalent roller bearing? Similar problem with the double row 5204 equivalent.
But, perhaps a spherical bearing would solve the problem?