I would not exceed the max pressure. I know it is a lot more wear on the pump, not to mention bypassing the oil filter. I did some research in my hot rod days and the general theme was not "more is better" Guys started using high pressure oil pumps in chevy's, based upon a real need for it in fords and they started burning up oil pumps (same gear design as lycoming).
I would not worry about idle. The engine doesn't need much pressure at idle. If I remember, Lycoming says 25 PSI is low end at idle. Be sure to check that figure, as my memory is not what it used to be. All engines have a lower idle pressure. You should be setting max pressure only. The low end moves with it and if it falls outside the idle pressure spec, you replace the pump or bearings, depending upon the cause. Plenty of old chevys running around with 15 PSI at idle and live for a long time.
Two methods to lower pressure, based upon your setup. Some have an adjustment screw. Older ones, like mine, require you to use washers (as shims) at the end of the spring to adjust pressure. You remove washers to lower the pressure. On the screw, it would be CCW, assuming standard threading.
Larry