I can answer the hygro calibration, rehydrating the sticks with salt that is a totally different process that I have no knowlege about.
Use a one to one ratio of table salt and water, this will give you an RH of 75%. The salt & water mixture should be pasty like wet sand not runny. I usually use about 1/8 of a cup of salt & water in a small bowl. If any water is on the surface after mixing, pour it off. Place the bowl in a ziplock bag with your hygrometer.
Analog Units: If it is an analog unit, let it sit 12 hours in the ziplock bag with salt before calibrating, it should read 75%. Using the adjustment screw on the back (location may vary read the instructions that came with the unit) adjust the hygrometer until it reads 75%. Optional steps: After inital 12 hours, place back in the bag with the salt & water, let sit and additional 12 hours. If the hygrometer does not read 75% adjust again and place bag in bag for 12 hours. Take the reading and if it varies from 75% this will be your standard deviation. You can continue to calibrate if you want but to me it is a waste of time. Note the standard deviation from 75% and use this for future reference. For example: if your hygro is reading 78% when you know the RH is 75% your standard deviation is +3%. So when it is in your humidor and you want to keep the RH at 70% you would look for a reading on the hygro of 70% + 3% = 73%.
Digital units: Most are not adjustable so you would note your standard deviation from above. My digital unit has a standard deviation of +3% so I know to adjust accordingly. I am keeping my cigars at 70% so when I check it, the hygro should read 70% + 3% = 73%
Use cigars that you are trying to revive. The point is to find their RH as a starting point for reviving them. Using cigars other than what you will be reviving doesn't give you an accurate comfortable RH for the sticks. Hope that helps answer your question!
If you have knowledge, let others light their candles with it.