You can power all 3 drivers via one powercord. 600w divided by 230vac means all three driver only draw 2,6A from the wall. Use 115vac and it would be 5,2A. I would just use a 3x AWG18(1,5mm²) powercord and three 3 or 5 port Wago clamps, one for blue(N), one for brown(L) and the 3rd one for the ground wire. Connect the according driver wires to these 3 Wago connectors and they will all be powerred via one powercord. They are still dimmable separately!
To switch them on and off you could use a Sonoff Basic for each driver. Sonoffs are digital timers but instead to plug them in the wall plug they are directly connected to the input lines(N&L). They are controlled via Ewelink app, cost only 5 bucks each and the new version BasicR3 can also work without internet connection. You can also add them to your home automating system if you want.
There a 1, 2 and 4 channel controllers available. If you plan to add a small far-red flower initiator I would recommend to use the 4 channel Sonoff. You would have 4 devices in the app and can set up to 8 timings per channel per day(4 times on, 4 times off). Minimum 1 minute! They are available with 10 or 16amp relay, with 230vac they can switch 2200 or 3600w, with 115vac it's 1100-1800w
There is also a Sonoff TH(temp humidity) which has a thermometer probe and is able to switch based on the sensor readings(14 bucks incl. probe, can switch only one device based on temps or humidity). These also store the data in a curve so you can monitor groom conditions easily.
A Sonoff POW can monitor power draw and is also useful. I also like the Basic RF which has a small 433MHz remote switch. This can be use as emergency off just in case you get unwanted visitors. Its just laying next to my main door and I just need to press off to stop my whole grow equipment.
I always buy them directly from the manufacturers website and they have many more versions like I have mentioned above. They work pretty good and because the timings are stored inside a small chip they only need internet connection when you use the app. I've just added a small 5$ wifi repeater to my groom and only switch it on when needed.
That's the BasicR3
https://www.itead.cc/smart-home/sonoff-basicr3-wifi-diy-smart-switch.html
