sorry can not help you
but i do like your setup
very neat

you can make cycle timers for around 20 bucks. if you dont think 100 bucks is worth it, why not just try 15 on 15 off with some cheap lettuce plugs? id just go 24/7

do not do 24/7. you dont need a $100 timer. Go with 15s, then adjust. Thing is with hydro, there is no blanket answer for watering times. In FL, you may need to do 15:5off, in CHI, you may not need so much. Climate is a big factor.

Gat a good digital timer ~$20

Or go with drip system, they are a bit easier to manage.

I have used aeroponics before I settled on deep water culture or bubblers. The thing with aero set ups is the roots cannot dry out and this gets tricky. With ebb and flow, the rocks or substrate retain some water and thus do not dry out. In DWC, the roots hang into your solution which has an airstone supplying huge amounts of dissolved oxygen and thus no dry outs either. With aero I found the best solution was let it run 24/7. It will not suffocate your roots one bit....just wear out your pump faster and for me that became aggravating. Bottom line with aero....use what ever timing you need to ensure the roots do not dry up. That may work out to 5on10off or whatever it takes but keep in mind that if your power fails so do your plants. Have you considered using a DWC system....just add water/nutrients and an aquarium air pump attached to a airstone in the bottom and kabloom! TO be honest, I grew lettuce using this method and to date...simple, effective and super easy with unbelievable results. Once you go hydro.....you will be hooked because I swear they grow in front of your eyes!!