Can’t answer your second question, but for the first, I think you should clean and re-lubricate the areas of friction (the “hat” area and pivot area). There’s an official variant of Shin Etsu lubricantthat Sanwa uses. Personally I use a small bit of white lithium grease since it’s cheap and readily available, admittedly I can’t feel a difference versus the stock lubricant but I could be mistaken.
I’ve only done this a few times, and I’m gonna go from memory without a JLF in front of me, but this should be enough to help you refurbish yours. I like to use qtips and paper towels to clean, maybe some alcohol would help but I’ve only needed to use it on rare occasions to remove stubborn dried stuck-on lubricant.
Let’s assume you’re looking at the bottom of your JLF. There’s a clear restrictor attached to the black stationary piece by 4 clips. Push in the clips with your fingers one by one (or maybe two at a time) and lift it out, this should come out with minimal effort.
On the shaft, there’s a curved E-shaped clip with two small gaps. I get a small flathead (a cheap one which I don’t really care about), stick it in a gap, and pry the clip out of the notch it’s in. You can usually pry out a gap then pry out the middle and get it out, you may need a pliers to pull it all the way out.
Once this is released, you have the actuator and spring. The spring is going to want to spring out once you release the clip, so you should cover the top of the actuator with your finger as you release the E-clip so they don’t run away.
Beneath those is the “hat piece” which I don’t really know the name of, heh. I can’t remember for sure but I think there is some lubricant on the hat piece (on a Seimitsu I cleaned/lubed there was lubricant on it). So assuming I’m right, clean the flat part of the hat, and the flat area of the black stationary part it touches, and be ready to lubricate them later.
Now you can turn the stick rightside-up pull on the balltop to pull the shaft out of the stationary part of the JLF. There’s a white pivot attached to the shaft, both it and and the bowl shaped area it goes into are an area of friction. Clean the pivot and the bowl. Lubricate them (you don’t need to use tons of lubricant nor should you, a very thin layer of white lithium grease is enough for me, dunno about the Shin-Etsu lubricant). Put the shaft and pivot back into the stationary part, with the round of the pivot going into the bowl, and the flat part of the pivot facing the balltop. Play with it to make sure you have a good amount of lubricant. If there’s a lot of lube, at least with white lithium grease, it will feel sort of tacky, (I guess there’s enough that there’s some fluid surface tension that it needs to break?), so clean them back out and use less. You want your stick to feel smooth and unrestricted.
Now that the shaft is back in the stationary part, flip the stick upside-down again. (Again, I’m not 100% sure this area is lubricated, I’m writing it as though it is.) Lubricate the hat’s flat part and the flat part of the stationary part. Slide the hat onto the shaft so the flat part is against the flat part of the stationary part. (This isn’t really easy to test as-is, perhaps try applying light pressure to the hat to keep it against the flat part of the stationary part, and make sure it feels smooth. If not, test it after assembly, and it it feels weird, it could be the hat/flat part of the stationary part needs less/more lubricant since the pivot/bowl is easier to get right. Though if it feels weird after adjusting the hat’s/flat part of the stationary part’s lubricant, try adjusting the pivot’s/bowl’s too)
You’re almost done. Put the spring around the cylindrical part of the hat, touching the outer side of the flat part around the cylinder. Put the restrictor onto the spring so that the bowl area is around the spring, holding it in place, and the cylindrical part of the restrictor is pointing towards the end of the shaft. Put the E-Clip into its groove (you’ll want to press the restrictor in a bit in order to expose the groove) and use pliers to snap it back into the groove. Put the restrictor on and test your stick.
If it still feels weird, disassemble and clean and relube. If it STILL feels weird and you used white lithium grease, then maybe I’m wrong about how well it works, and you should get something more similar to that Shin Etsu lubricant (I’ve seen the brand Moly Kote thrown around as an alternative but I’ve never used that, nor have I used the Shin Etsu lubricant (aside from it coming on sticks from the factory)).
Whew, long post