rear airbag and suspension travel

on my recently purchased 2013 DCLB it has the 3-Leaf pack and the firestone airbag with 2 bellows. i've never ran helper bags before so my question is, what would be the limiting factor of suspension travel as i will go off road, nothing too extreme but washed out road crossings from flooding will flex the suspension fully.

stock shocks, max droop of leaf springs, brake lines or the air bags? which one will be the limiting factor first?

id love to have full usage of the suspension travel while still keeping the airbags as i will eventually put them on an electronic valve to inflate/deflate from inside the cab once i get on board air at a later date.

also, as to not create a new thread. for rear lift once the truck is paid off, using a 3 leaf icon aal, would there be any reason to get the TSB leaf, or is the 3 pack plus aal fine? airbag will remain

 

also, assuming the airbag will be the first to limit, has anyone used a 3 bellow bag to allow for more travel, or let it freely float on the lower mount?