Consider .....So what I find is the weight of the fly (as one major factor) and leader will help dictate the line choice. Given that many permit flies I know of are weighted with lead eyes I'd be likely to pair my 9 weight meridian with the grand slam (or similar) line for permit fishing.
Also consider the leader, e.g. stiffness and length taper ratio. Increase stiffness in butt and mid-section, and if necessary reduce lengthYears ago, the answer was to step up to a heavier rod and line size when the flies became troublesome to cast. That is still a good answer today.
Agree, if I was just targeting bones I would use a longer bonefish taper.I used the air flow for a it as well - great for shot at LA bull reds but for me I struggled with delicate presentations at longer distances and preferred the rio permit for chasing bones in FL and Belize.