Definitely handy to have the water sprayer as auto. On the GC8's it's pretty easy to push the hazard light button instead of the I/C sprayer. On hot rallies its not uncommon for me to plow through 10L of water in a couple of stages.
There is a reason that the factory had a timer on the sprayer and it's not just to conserve water. The water needs to be sprayed and then air needs to pass through the wet IC fins to give better cooling. Aledgedly its more efficient than just continuously flooding the IC.
Most after market
ECU's can be configured to trigger the I/C sprayer at set boost positions or IA Temps in the map. Maybe ECUTEK has a similar output to hook up to the factory timer?