How many extra alts do I need?

[BigHurt77]

I've been running 1 Mechman 370 amp alt. with 5 XS Power D7500 agm batts since the build was 99% complete 4 years ago... Its time to upgrade to a 90ah Cmax lithium. The question i have is... How many extra voltage regulated alts will I need maintain 15.4v at full tilt? I'm running 4 RF T2500's for 2 T3S219's. 1 RF T1000x4 for 4 Punch Pro 8's for now... 1 T400x4 for 2 Super tweeters. And a RF 360.3.  The truck is having a bracket built to add another alt next weekend. The potential of a possible 350 amp draw per amplifier bothers me.  Please Help...