I have the same problem, oil light flickers once warmed up slightly. Then once warm it takes a bit of revs's to turn the light out. And if left to idle it is hunting once warm. I do not know the pressure, need to check.
Just had new Piston rings, Big end bearings, Oil pump, Pressure switch, Oil and Filter.
Solved it? Nope!
Reason i went the route i did, it was smoking out of the head when oil cap was removed, some black smoke when driving normal from exhaust, chucking oil out of the breather, not masses but certainly noticeable and the hunting all lead me to Rings. The above was only done recently and i have not had chance check these symptoms since. But it does still hunt on idle.