In theory it should keep them cool.
There is a test on a german site:
https://www.computerbase.de/2017-02/palit-geforce-gtx-1050-ti-kalmx-test/3/They have the highest Temepratur with Anno 2205 and with their Testconfiguration 1 (CPU cooler 150mm @1000rpm, front fan + back fan (both 140mm) in the case @1000rpm) it keeps the card pretty cool at 61 Degrees celsius...
I am just not sure how much fans one would need if you have 12 of them in an open air rig...