I struggled a lot at the beginning when buying saltwater from various LFSs. I never found a place that sold water with consistent enough salinity or parameters, so I started making my own and the health/growth of my corals improved by leaps and bounds. Good job for taking what I consider a very important step! I haven't tested many different salts, so I'm not much help there. I use Red Sea blue bucket and have never noticed huge differences in parameters from batch to batch.
Two tips for mixing:
1. Never trust the advertised volume of a container. If you start using a measuring cup to fill different containers, you may be surprised at the results. I have a mixing bucket that I painstakingly filled using a measuring cup, marking each gallon as I went. Only had to do this once, now I can easily know exactly how much water I have.
2. If your saltwater batches are small enough, measure salt by weight and not by volume. You can use an online calculator to estimate the weight per volume the first time you mix, and then adjust as needed after measuring the salinity (the online calculators are never 100% right ime). You only need to do this carefully once, then you know the weight of salt needed.
Doing it this way you have a quick and repeatable method for mixing a certain volume of water to a specific salinity. I always test when I mix each week, but the salinity is always spot on without need for adjustment. Again, this is impractical for large volumes of saltwater, but works well for nano tanks.