Thanks for all your answers! Basically, I wouldn't be removing large chips from thick boards, I'd only need the hot air for working on maybe 4 layer boards maximum. So the smaller air flow might be sufficient.
Each circumstance is different but proper technique is using gentle heating from the top or from the underside to slowly bring the board up to a preheat temp. It reduces the thermal energy required to then reach reflow at a high temp.
If you were looking at a complete setup to do almost everything, get a hot air station that is capable of large BGA rework (so nozzle selection is an important part of this) a preheater and a hot air reflow oven.
For precision stuff this is my Pace TJ 70 handpiece with it's range of tips, it's a more specialized tool designed mostly for installation but it does soldering, desoldering, conformal coating, track repair, heat shrink, connectors etc.
It has a couple of advantages, while temp and airflow are controlled by the station there is a switch on the handpiece that actuates the air. It also can be controlled by foot pedal, so it's happy to just sit there without airflow if you want. This also means you can use it hands free, which has a variety of uses.