Im fitting an trailtech vectra style electric computer thing on the dash as im running a rallye style fairing. This comes with a pipe piece you put in the outlet radiator hose after the thermostat, the pipe piece has a sender in it for my computer thing. You could run a switch with an idiot light from here. ( parts avalible seperatly from trailtech)
I was gunna run a oil pressure guage but not going to bother now, just another thing to go wrong.
An oil temp light would be worthwhile though as there is not a cooler on the bike. Im gunna run a cooler.
You could drop the sump drill and screw an adaptor in and again run a switch to an idiot light.