I have the 6" Can Fan Pro Max Fan you mentioned. It is more powerful, has higher flow rate (410) , than many/most in its class; is very quite (with a Phresh muffler), with the only/most noise being a soft 'whir' when as the turbine spins-up; and has a speed controller built-in (and I've at most used the medium setting in a larger, 12.5 sq. ft., tent, formerly with near 1000 watts LEDs, now with AuoCOBs I cut back power use about 40%).
If you want a thermostat (which is way better than trying to balance fan speeds using manual speed controls), I suggest use a digital controller, not an ancient (-looking; mechanical?) Titan thermostat, which also look to cost much more. I use the Lux WIN100 "programmable outlet" thermostat (usually in $30 range). I have it set that when temp. goes 1 degree above my set. temp., the fan comes on, and turns off when temp. goes 1 degree below my set temp. Works great; never have to worry about tent getting too hot.
If you want a thermostat (which is way better than trying to balance fan speeds using manual speed controls), I suggest use a digital controller, not an ancient (-looking; mechanical?) Titan thermostat, which also look to cost much more. I use the Lux WIN100 "programmable outlet" thermostat (usually in $30 range). I have it set that when temp. goes 1 degree above my set. temp., the fan comes on, and turns off when temp. goes 1 degree below my set temp. Works great; never have to worry about tent getting too hot.