Yes on consulting your manual for salt level. I'd reccomend testing independently of what the SWG says the salt level as well. Most SWG (I think) have an ideal salt level around 3500 but will still produce chlorine at levels above and below that.
For the CYA I didn't do the math to confirm how many pounds to get to target for your pool but it that was it then go ahead and add it in some socks to hange in front of a return. It can take a while to dissolve. You can check CYA before they are completely dissolved and if it has hit your target remove them?
The test for CYA is subjective and does require being outside in full sun with your back to the sun. It sounded from previous posts that you were pretty sure there was no CYA so go for it.
Doing everything the "TFP" way is only learning what your pool needs, why and only adding what it needs by accurately testing your own water. You're on your way