the bottleneck in airflow seems to be the hole in the 3V atty. the 6V atty had a larger hole bored into it by IMEO and drew much better. i have a drill press and may try to DIY.
ps ive found no leakes without the o-ring mentioned above. furthermore the heat from the atty seems to deform it.
o-ring cant get deformed my friend shaun because the temperature at the point where o-ring sits is very very low. O-ring is made for more than 100 celsius degree and the point where o-ring sits is so cool that you can touch it by hand easily