Never thought about lowering pressure but maybe using a thicker gasket on the oil pump cover??? Other than that, the things I am thinking about involve removing the engine and tearing into it.
It seems that it should be possible to mount a mechanical gauge in the place. I know on the other end, the take off is simpler and smaller so that side should not be a problem but I certainly understand NOT wanting to undo the GNX type dash. ****It would, however, be a good idea to at least verify the oil pressure with a good mechanical gauge before making any other changes.****