Ed,
I run a Melling Hi-volume pump, and I replaced the spring with the Ford Power Parts hi-pressure spring. My side-oiler block also has a relief spring at the rear, which I also replaced with one from FPP.
Anytime you install a new
oil pump, always disassemble and clean it, as they usually have some leftover dust from machining.
As Don pointed out, the 10psi/1000rpm minimum is a general rule of thumb, FE's really need more than this.
I also have .093" restrictors in the rocker shaft feed holes, and the lifter galleys are blocked, as I run solid lifters.
I run a chrome-moly
oil pump shaft, and a Bronze distributor gear to avoid wear on the cam. I replace the bronze gear annually.
As far as servicing the motor in car, you can replace rod bearings fairly easily, and mains with some difficulty, but getting accurate measurements will be tricky with the motor assembled.
Check with George Anderson for advice on this.
About the pan, a properly baffled pan and pickup will help maintain
oil pressure during hard cornering, accel and braking, but shouldn't make any difference while stationary.
Good luck,