I would not use seperate inverters, if you did they could not both be connected to the same AC cable at the same time, unless they were disigned to be stacked, that is both units are syncrinised so the AC wave form is the same. In that case one inverter would provide the time base for both, but I suspect this does not apply to cheep inverters.

Bottom line look at the specifications of the inverters you are planning to buy.