I Heavy Haul and just use the standard KW bags (I do carry a spare). The lift axle has Hendrickson air bags and is rated at 20,000. My trailer is a TK 3+3+3 with Hendrickson bags. Most I have had on is it 198,00 plus my normal empty weight of 78,000 with no problem and that one was on some pretty rough roads going into a mine.
I take it when you are saying 13.2 front end you are meaning 13200 front axle, not enough !!! need a 20,000 front with 12 inch tires.
When HHing always best to spec way beyond what you think you might need, both truck, trailer and tie downs. Load I have on now, by FMCSA only needs 9 1/2 chains, sucker has 14 and that is only because I couldn't find anyplace else to hang one