First, I would
buy the 316L version FT has, or the Tobeco. The Tobeco is made much better then the linked. As for air flow, it is a bit more then the GTII-S I have, More then the KF4 with 4S kit, A bit more then my Gem, roughly 2x the air flow of the GSL with just the bottom open. It has a good range of adjustment, from very tight to restricted lung hits, base airflow inlets are 2x 2.3mm max down to a single .8mm, under coil is 3.5mm.
3FVape also has a 22mm version with a glass
tank, haven't tried that one yet, FT also has a glass tanked version I haven't tried, but it is 23mm.
Overall I like it, pretty much vapes like a GTII with a bit more airflow. Posts/screws are also nicer to work with then the Taifun.