Plumbing two NFT systems together

I want to run two GT424 NFT systems together. I was thinking, should I connect them together by drilling holes into both systems' reservoirs and connecting them with 25mm tub outlets and pipe from Greens? I'm currently using a chiller so I worry that one of the tanks might not get enough of the cool nutrient solution to keep the res at 19°C. Any advice or suggestions? Oh yeah, one of tanks (the tank I have set up now), is connected to an auto top-up valve so in theory both when connected together would get topped up when the nutrient solution level falls.

Why have two reservoirs/tanks..?

The best way I would imagine is to have both try’s going into one reservoir/tank...