Cvriv I’d personally stick with the two 3amp chargers, Unless you really really need ultra fast charging? Even then, I’d still only use ‘fast changing’ when really needed. Batteries are way better off being chared at a slower rate for many reasons…..
I have a 50ah Battery in my Weped FS - It comes with a 1.7amp charger, it takes about 28-35hr to charge - Early on when i first got the FS Ihated waiting, so ordered an 8amp charger, this shorten the time, But about 2 months after the battery started cutting off at 75V - Long story short, had to get an entire group of cells replaced, not saying it was the fast charger, but after replacing the cells and only using the slow 1.7amp charger, the battery been fine and its been 6 months on… I never use the fast charger any more…..