Yep, I agree you should wait at least 24 hours before using newly mixed salt. PH and salinity especially arn't stable right away. This is why Its recommended to if possible always have some water on hand already made incase of emergency.
I should have clarified in my earlier post - I usually do have a power head ( just need to get a new one, old (crappy) one broke) so I had to make due when I needed water change. The one I had before didnt mix well when putting salt in, hense why I used my hand to stir in the amount needed for the right salinity. I make the water sunday usually and use it wednesday, stirring occasionally, especially before I had to use it. Not ideal, but it works in a pinch. PH is ordered
( better one this time!) - a good lesson to those reading - spend the few extra $$ and get good equipment... its cheaper in the long run!
But back to the topic, salt choice depends on preferance. If you find one you like, and everything seems happy, stick with it. You can change if you like, but most seem to stick with the same salt. I dont think theres one 'best' salt.. lots of different opinions on it. I know a lot of people go with thats available in their LFS