Stay away from the sharp inverter, its the second lowest efficiency rated in the CEC list at 91%
For your three strings, having one shaded will have next to no effect to the panels in the Sun. This is because solar cells are basically diodes. In order for them to SINK current, you have to exceed the reverse breakdown voltage which is above the VOC rating of the panel.
So, a panel dark in parrallel with one in the sun will never have this happen. Having designed and spent endless months montioring,testing and tweaking systems I'm convinced independant tracking strings is a sales gimic. It will make no measureable difference in the harvest as compared to a single input invetrer.
The GT3.3 will be sold for more than the 3.0 I am told, both are the top performers and best in features in the Gridtie market. You should build, install your system upto the point the inverter needs to be installed, which is the simplest of the steps. based on $$ at THAT time, buy either the GT3.0 or the GT3.3.
Lets use know how your Sanyo's perform and also what the costs is please
. I think on my next system I'd like to use them but I'd like to see some real world data over a year or so to see how the hybrids hold up as Asi is Junk as shown from real world use.