Went through the same process last year and we decided on some dead-simple HD battery packs that would take anything we could throw at them, so we ended up buying some WELL-used discontinued Dynalite XP1100s. Swapped-in some new after-market batteries and the things are utter beasts.
They last forever and the suckers are powerful. The recycle time of an Acute 1200 pack, at full power, on slow recycle off 120AC is app. 3 sec. On a Dynalite it's 4 sec - and it's not even trying hard. A full-power D1 500 recycles as fast as if on AC.