Until you get stocked with corals and/or have lots of coralline algae growth, you shouldn't need to use kalkwasser or a calcium reactor. Just pick a salt mix with slightly higher dKH than your target and you should be fine with routine water changes for a while. The Red Sea Coral Pro has a dKH ~ 12 which might be a good choice.
At some point, calcium and alkalinity will be removed from the water by corals faster than the rate it is replenished with water changes; you will know when your dKH starts to trend downward. That is a good time to start dripping kalkwasser. I use an Avast stirrer attached to my ATO and it works very well. I actually started using it too soon and my alkalinity drifted up to about 14, starting with the RSCP salt which was ~ 12. I have gradually lowered it to about 10 with 8-9 the final target.
Ultimately fast growing SPS corals will deplete calcium and alkalinity faster than water changes plus kalkwasser can replace it, at which point you could decide between dosing two part solution or installing a calcium reactor. The latter tend to require a lot of fiddling and maintenance, at least in my experience with a Deltec unit. Seachem also makes an inexpensive tablet that some maintenance guys swear by, as levels drop it starts to dissolve and raises them back up.
Have you thought about nutrient export with carbon i.e. biopellets, vodka, zeovit, etc. ? I tried Zeo years ago but found it too much work; vodka dosing was effective but didn't like the stringy bacterial growth I'd see in the display; this time around I am using biopellets which seem to be the best of both worlds.