Oil pressure question...I promise it's not another "who likes what' thread!

Thanks for all the good discussion...so for an update, I slipped a .040 washer under the spring, and picked up between 5-10 psi from about 1500 rpm all the way up. It did not raise the idle pressures but did show an effect over the rest of the operating range. So Ima callit good at this point, and mull over the options of 50 grade or 40, synthetic now or later etc..