The closer the baffles and jackets hug the jug, the better the cooling. All important is the pressure difference before and after the baffles. Guiding the air after it has left the cooling fins is of minor importance, as long as the air extraction is working well in creating that pressure difference.

@ soarrich,
It took a few demolished plugs in perfect shape, but was the only way to show the differences between mixture strength and plug heat range.