If you are still looking for a simple solution i have been using this combination for 6 months now, with no issues so far.
In theory the 30A ps covers only 1 speaker, due to peaks in power, even if i've never had any problem
running one speaker off a car cigarette lighter plug, fused at 20A.
Still, i would buy 1 for each speaker since they are quite cheap.
They do sell a 50A version but I have no experience with that.