Shading panels with cardboard or something will lower current enough that nothing can be powered by them, but they may still produce sufficient voltage and current to electrocute you.
The way to work with PV while the sun is shining is to use the touch-safe MC connectors to isolate them while you work on other things, then mate them. Only mate/unmate with no current flowing.
By cutting an MC extension cable in half, you have a pair of pigtails. Connect them to a single panel for relatively safe voltage, measure with DMM to get polarity and color-code. Then do all your wiring with MC disconnected from PV.
I check Voc of each string by sticking DMM probes in the ends of the connectors (keep fingers off the exposed metal of probes.)
By "4 inputs" so you mean two MPPT inputs, 2 positive and 2 negative terminals?
In that case, ideally 4 poles of isolation, which that knife switch doesn't provide. Midnight 2-pole circuit breakers (if correct voltage) can isolate both ends of one string. Looks like theirs aren't high enough voltage, 150V per pole.
"I will have two 360V strings and two 240V strings. I think that is correct. 40 VOC x 9 panels = 360V"
Nominal, higher for max Voc spec of inverter.
I guess you would join two 360Voc in parallel (check voltage between the is about zero before connecting both ends of string), and two 240V in parallel.
Disconnect for your 360V (or higher) string is a bit more difficult. Midnight's breakers are 150V each, so would need 3 ganged in series.
Here's 4-ganged for up to 600V (also has remote trip)
MidNite Solar Product Page.
www.midnitesolar.com
Four touch-safe fuse holders would open both ends of two circuits. Not for switching under load.
MidNite Solar Product Page.
www.midnitesolar.com
These fuseholders are cheaper than normal:
Shop for Midnite Solar MNTS at Inverter Supply for best prices online. Midnite Solar MNTS, Midnite Solar, MNTS, Fuse Holder 1000 VDC Din Mount For Midget 10 MM X 38 MM Fuses, Midnite Accessories
www.invertersupply.com
Schneider has some products:
View the A9N61537 product features, specifications, documents and FAQs. Acti 9 Circuit Breaker C60H-Dc, 500VDC, 40A, 2P C.
www.clipsal.com
(not cheap!)