If only used for the track then a "normal" switch panel thing might be a good bet, but otherwise it is very easy, using a heavy duty ON/OFF switch and a heavy duty momentary push button switch, I have a illuminated push button start switch to go in mine in red, but can get these in blue as well for around £8, these are illuminated and when wired to the oil pressure sender wire serves as a extra warning light for the oil light.
Just do a check on the ignition switch to see what wire is what in each position inc the start wire, then live in and out can be put either side on the main switch, then a live from the out of the main switch to the starter push button, so starter will only operate when main switch is on.
tabetha