The weave is very important, but is one of the easier things to determine. For example, a voile (though uncommon in men's shirts) is much lighter than a moleski

The weave is very important, but is one of the easier things to determine. For example, a voile (though uncommon in men's shirts) is much lighter than a moleskin though you would never find a summer shirt made of the latter. As someone who also sweats freely, I sympathize with you. If wearing a single shirt, I tend to go with a darker color for that reason. If wearing a dress shirt, I'll always wear an undershirt with it. There was a semi-famous US Army study about thicker cotton shirts feeling cooler in the heat since they can absorb more of your sweat than a thinner shirt. I can't attest to its accuracy. I wear them so I don't look like I just came in out of the rain.