I think the answer is no...if you consider the cooling system holds around 4 gallons... you should have a 2 gal coolant and 2 gal distilled water. If you have lesser concentration of coolant than the properties and protection are reduced. Only real way to check is to use one of the coolant checking tools that "float the balls".... half and half is where you want to be.
...or you could buy ....http://www.amazon.com/Prestone-AF-1420-Antifreeze-Coolant-Tester/dp/B000BOA9RY for the amazing low price of $7.00 and quit guessing?
Pps water wetter is designed for track cars/bikes that are not allowed to use coolant. Basically a waste of money in anything other than straight water.