Although I tented the JMT, I have many nights in hammocks. Hanging the JMT has been discussed at Hammockforums.net quite a bit. Each night I looked up from my tent and thought “I could have hung here too” except at Guitar Lake and Wanda Lake. I will likely hang in a hammock next time I do the JMT but I will bring a shorty pad so I can go to the ground if convenient.
Extreme weather is possible any month along the JMT. I experienced swirling gusty winds from every direction on two nights. I’d recommend a tarp with doors like a Superfly for just a couple more ounces.
I think at 40° TQ/UQ is not enough insulation unless you are an absolutely hot sleeper.
You need rain gear.
I find Prana Zions to be extremely warm for hiking above the mid-70° range.
190 weight T-shirt is too hot for my taste. I’d rather at 150 weight.
Prophet is an MLD pack not GG… That said, I can’t imagine carrying a bear can in frameless pack unless you are carrying a small capacity can and doing really long mileage days (less food).
Raingear would be a good thing.
I carried a Sawyer Mini. I feel like I lost a fair amount of time over my three weeks filtering slowly. I’m tempted to take a UV filter so I can just zap it and keep moving. 10 minutes several times a day would add up to a lot of time over several weeks and would allow me to take breaks more where I wanted to rather than feeling like I should take my break next to some creek that didn’t have a great view.