The lower the gauge, the thicker the wire, the lower the resistance (i.e. 28g is thicker than 32g and also has less resistance). Thicker wire has more surface area (due to larger diameter) than the same length of thinner wire. Greater conductive surface area (current passes on the OUTSIDE of the wire, not through the middle) = lower resistance.
With the SS mesh, the higher the # the smaller the particle that can pass through the screen. Filtering, sifting, sieving, etc is irrelevant to you, but what is important is capillary action. The higher the number, the smaller the squares that comprise the mesh. This means that the wires that make the little squares are closer together and smaller droplets of liquid can travel from wire to wire based upon viscosity. Theoretically, the smaller the squares, the better the mesh wicks. So, a higher number means smaller squares means the mesh will wick juice better. #325 sometimes is strictly gravity fed and doesn't wick well via capillary action.
If your wick is bursting into flames, it usually means 2 things are happening: 1) there is excess juice near the coil; and 2) your coil is burning hot (hotspots or too high voltage). Check your coil for hotspots. Excess juice is usually a good thing (means good wicking), unless you overdripped or leaked.
