Flore

Sunsynk 3.6kw or 5kw inverter. I'm biased towards sunsynk inverters as I have their 8kw unit. 
It just works. I'm not sure how many are currently installed in SA but there seems to be very little issues being reported or user complaints just looking through the threads on this site. Mine has been running now for four months with not a single issue yet. Some software bugs was sorted fairly quickly with updates pushed through via the Internet. 

Well, I'm not a fan of high voltage PV strings either, so I would have wired them 2S7P with one of the Axpert MKS models (not an MKS II). But I don't even know if they make a suitable 24 V model. I'd pick the one with the highest PV power; some of the 24 V models are really stingy with the built-in PV charger.