For your set up, I would skip the blocking diodes.
You will not have times of good direct sun,with any of them shaded.
They would only prevent power from a sunny panel from going backwards through a shaded panel.
And I do not believe that actually happens because a shaded panel still makes enough forward voltage to hold back the reverse flow from the sunny panel.
I do not recall being overly impressed with the Juta controllers, but they will have a blocking diode provision.
If you want to install blocking diodes, a 6A05 on each of the smaller PVs, and a 35A bridge rectifier on the large panel would be fine.
I would recommend installing the bridge using 2 of the internal diodes.
PV+ to both the ~AC bridge terminals. Bridge + to the controller + input.
And use a big heat sink.
If that is not clear, there is a sketch here.
Replace "Ametek" with PV, and the controller is between the PV and battery.
http://i701.photobucket.com/albums/ww20/ghurd1/Sketches/BridgeAsBlockingDiode.jpg
Debating the implications of direct importation of assembled controllers.
You guys have some funny rules.
And even assembled, they still are not 100% idiot-proof (one of my top priorities for assembled items).
G-