I reckon a bigger than standard cooler isn't a bad thing.
As long as it let's the engine warm up, to between 60 and 70 degrees it'll be fine.
Oil pressure is pretty low in them standard, i know the z155ho are around 10psi at idle and are around 30-35 psi at 3000 rpm.
the oil coolers are plumbed up to intercept the oil flow to the head and rockers, so deliver cooler oil to the top end first which the drains back through the cylinder to the gearbox and bottom end.
I haven't checked around for high volume pumps for the daytona's yet