If you're not using it for racing, but you insist on running something other than distilled water between race meets, just use regular coolant. There's no particular need for fancy stuff at a track day. Or if you care about your fellow track-day punters, just use some Penrite Sin Race coolant (glycol free). But I can't recommend distilled/demineralised water enough! You can dump it out after years and there's no rust or discolouration at all - it's still clear, clean water. The only reason to use coolant would be for you poor people in Canberra that have to worry about breaking water pumps when the water freezes in the engine before a day at Wakey......

Water Wetter is bad, m'kay. I've looked into it in-depth before; essentially it gums up your engine with nasty, sludgy deposits. Do some googling and discover how maligned it is.