Oil cooler and oil pressure gauge

Maybe many of you may think it's unuseful to put an oil cooler on this bikes, but in Madrid we reach 113 degrees in august... Has anyone put one of this on his bike? I've seen Norman Hyde's one, but I wondered if, for example, a Citroen 2cv cooler would fit as I've seen on old Harleys.

On the other hand I was thinking of getting an oil pressure gauge, as I've had oil incidents before (some of you may know...) and I don't find any suppliers for this item here in Europe. Any suggestions?

Many thanks to you all!

If you put an oil coller on make sure it is contolled by a thermostat, no point in it being in circuit unless its needed.