+1 new head
+1 limitor
+1 new cabs
i had huge issues myself with blowing drivers. some were manufacturing defects, some were limitations of the equipment i was using, and other times it was technique.
my right hand techniques goes from barely touching to steve harris clacking, my basses are all pretty hot (emgs, or stringrays). i use distortion and octave sometimes. this causes a huge mess when combined with the wrong cab, head, etc.
i once had a ampeg 350 head. it was happy as can be when it was powering a single 15" cab. the problem was that when i hooked it up to multiple cabs or a really power hungry cab, and turned up the volume and eq (combined with a hot input bass and sloppy technique) i "underpowered" and was close to damaging my head and cabs.
i also had really crappy luck with classic ampeg 410s. just a real farty cab, never liked it, always let me down. if going ampeg 410, go with the pr410hlf armor plated one. sounds great!
2 things solved my dilema. bye bye ampeg 350, hello gk neo 212s, hello (again) GK 1001rbII, hello zoom B2 medium limitor setting. this allowed me to put my tone at a slightly squashwed, slightly lower level into the front of a head (with tons of headroom) and into cabs where i control what goes to the tweeter (GK neo 212). the zoom b2 limitor setting (medium) really helped me a lot. i have had 98% no issues since doing this.
as far as loudest speaker. so many variables,because sometimes the best drivers matched to the wrong box, sound like poo poo. check the xmax rating. but i might say EV cast frames.