I hear you about not being able to monitor the gauges, that's why I suggested some sort of loud buzzer like we have in the boating and small aircraft industry. Boat owners, who have all the time in the world to monitor their gauges, never seem to notice their temps getting out of control(clogged cooling water intake, etc can make this happen pretty fast in a fresh water cooled boat engine) but we find that a loud buzzer ringing in your ear or a very bright "idiot light" makes it hard to ignore when your engine is well on it's way to a thermal meltdown if not dealt with "right away". I'd suggest a buzzer(loud enough for you to hear it over the wailing engine and through your helmet) as that will not effect your driving where as a very bright warning light may well interrupt your vision.
Anything you can do to improve oil cooling will likely help take some of the load off the air cooling of the cylinders/head and afford you some extra leeway. If there was a reasonably simple way to tap in a cylinder head temp sender(there are systems that mount under each spark plug like a washer with a wire coming off it), like many small air cooled aircraft engines have, that would give you another data point regarding knowing where your limits are. I'd think setting up for an oil temp sender with a pre-determined temp limit to trigger the buzzer and gauge would be the easiest to install and offer a reasonable piece of mind so you can concentrate of racing rather than your mechanicals. This way, the engine tells you if it is past it's limits, at least the oil temp limits that you set.
So if your racing, and the buzzer goes off, you might have to back off a bit to allow your engine to cool back off to safe limits. If the buzzer doesn't shut itself off within a reasonable amount of time, it may be a bad sign for your motor. If the buzzer does go back off, you likely backed off enough that your oil temp went back into a safe range allowing you to continue on and if you feel brave you can ride the limits of the buzzer(safe max oil temp limit)...
Naturally, if the buzzer never makes noise, that would be fantastic...
Perhaps this is WAY over thinking it, but I was considering something along these lines for myself anyway as we use this type of system all the time(in non motorcycle applications anyway). I'm overly conservative regarding the idea of blowing up a motor when I might have been able to prevent it.
These are just thoughts from someone with way more personal experience in non motorcycle industries.
George