I would go for the tighter capris for 2 reasons:
The looser capris have a large proportion of cotton in them, so will retain a lot of sweat (not good). The greater the proportion of synthetic material, the quicker it will dry - think the tighter ones have larger propn of synthetics.
If the trousers do get wet (sweat/rain) it is more comfortable to have the fabric tight against your body, where it may dry from your body heat, than flapping wetly against you (speaking from experience). So tighter capris better