Can someone explain the advantage of having 2 smaller strainers vs. one larger strainer?
Both will need to monitored or they will clog. A larger strainer (1.5 - 2x) can handle either flow while 50% clogged and thus would be less prone to clogging at critical moments due to heavy weed.
A larger strainer will give less resistance when clean, since the AC and engine will not run at the same time (didn't mention generator
or that AC was engine driven).
I don't think this is actually a case for redundancy, unless they are interconnected (parallel). I see this behavior in process plants; a big strainer is maintained, smaller dedicated strainers see more neglect. I would have valves to isolate the systems in case of leakage or maintenance