Air coming from both sides would help lower humidity in the tent , I have a 4 inch blowing filter air in, and a 6 inch sucking filtered air out and a 6 inch blowing through my cooltubes to keep temp down , my cool tube has ducting that runs into an open exhaust vent upstairs to divert heat away from grow area , humidity will stay 45 without humidifier running,,, if I want to boost humidity I just turn humidifier on outside the tent , I have 2 just in case , but your trying to lower humidity sooo, more air flow through the tent will help and dehumidifier if it’s really that high , best of luck others may have different opinions as I’m a new grower myself but what makes sence makes sense.