Dear i will advise you to use 1600 AH battery bank (Even normal Lead acid battery,so that they may be alive till 2-3 year). Even these deep cycle battery will go dead in a year or an extra half with your setup and load ratio.
PV=Continuous load (or at min night load)
Battery=Inverter rating-PV {or Min 10% if PV Watt=Inverter Watt(0.8*VA)}
Ideally PV W= Batterys AH= inverter VA (W/0.8) assuming( continous and night load=Rated/2) for a good stable system