Hey Roscoe,
If wired through a N.C. Pressure switch or a switch that acceptable
oil pressure keeps the reserve
oil at the ready. Any pressure drop below the set point of the P. switch allows
oil flow to the engine from the A-sump. The enable voltage to all this can be an ignition source but I prefer a toggle SW.
In the end it is the same functions you have except the solenoid remains off in my case until needed and your uses the always on condition.
A few years ago I tried to find a solenoid with a high flow rate, rated for the temps of oil and oil compatible and with no leak down when turned off. I also wanted one that would allow flow in the fill direction but at a restricted rate as I was concerned it might starve the engine for those few seconds it took. Everything I found leaked down over the course of a few moments to a day or so leaving no pressure to pre-oil a week later. I wound up going to a supplier that configured or made just what I wanted but had to buy a min. # at a time as they were not self stock items.
I took the units that leaked down on put them on turbos as after oilers to cool them down and stop any coking effect so all was not lost. It took some tweaking but found I could get a 1 quart system to after-oil for right at 4 min directly at the turbo inlet.