I understand completely what you're dealing with as I deal with the same weather as you .
The rain has to be so bad that White powedery mildew is a issue to worry about the buds . I think your sceening will hold the branches but you can watch for brken branches and remove them . I had some brake before harvest .
The rain and the humidity will be the issue for the buds .
Blowing off your plants isn't such a far fetched idea if you can do it without blowing the buds off the plants :) .
If I could keep from harvesting by doing so you can be sure I'd have the blower out :)
I shake my plants to get the extra water off of them , if I think it's a issue .
Oct. here will be when we ususally get alot more rain , so as you are doing, keep an eye out for any rot after the warm back up time after it rains .
If you don't see any rot happening you have nothing to worry about but broken branches .
Rain is a good thing until humidity gets involved from warming back up the buds , that's when they rot .
I think you'll see White Powdery mildew showing up on he fan leaves before you see rot .
You can deal with the mildew with milk and baking soda , if that's a issue I'll tlak with you about that, it's nt a big deal to do and it works well .
The rain and humidity are a issue for me as I'm not in full sun , so White Powdery mildew issues .
Your plants are in full sun and have a better chance to dry out without issue after it rians as long as the rain doesn't just keep coming.
Then you do have a problem , but you take crae of that by harvesting .
So wait until the last minute , you'll see when and you'll feel it's time by the weather if you have no more sun coming .
The only reason I harvested is mine when I did was the buds couldn't last any longer as they were so far done. I waited until the last mintue to harvest and it worked out perfect . I was afraid they would rot from being so finished and wanted to harvest , but I held off and everything looked great when I did harvest .
That's the bud next to me now I'm working on smoking :)
If the rain doesn't stop and you waited until then , which I would unless my plants were done , go harvest in the rain and bring it inside .
As far as for the plants living off the soil , that's the way you want it towards the end of the grow season or the leaves won't change from green to yellow as easy from all the Nitrogen still being added to the substrate - soil .
My strain ate Nitrogen until they were harvested but they are Nitrogen eaters and yellow even with Nitrogen added until I harvest . The more leave the plant eats the less you have to trim later :)
I give my plants nutrients sparingly at the end so the plant eats itself - yelllow leaves .
Use your own judgement when to harvest by what happens weather wise , trust your judgement , you know and see what's happening in ral time there , so you'll be the best one to say it's time to harvest and why .
It hasn't been to bad weather wise here so far , the days will shorten even more every day , the plants will hurry to finish because they sence that . So hopefully less daylight will speed up your finishing time bud wise .
No nutrients , just water when needed is great as you're doing . Smoke on :) Hope all was well in your beautiful garden !