I have always used Kalk since it was the only thing available...
I also use it in my top-off water, (I think dosing concentrate would be risky, but people do...) Mix up 5gal in a clear water jug in the morning pour the solution into top-off container in the afternoon dump the remaining sludge down the drain. Some people will tell you to reuse the sludge to get the undissolved Kalk...I may be cheap but that is over the edge IMO since Kalk is inexpensive and the sludge also contains the crap that the Kalk precipitated out of your water...
Your levels are not entirely dependent on the evaporation rate, in that you can vary the concentration in your ATO to match the needs of the tank. Some people complain that you cannot change levels quickly with Kalk...Very true but is that really a bad thing? If you need to ramp levels up quickly use a different product and then use Kalk for maintenance after...or be patient.
I have always (unrelated to "carbon dosing") added 2tsp of white vinegar when mixing 1-2tsp of kalk/gal of top-off water to buffer the PH swing and help it dissolve more readily. One key thing back in the "tap-water" days that will benefit if your ro/di gets tired before you notice now, is that when you add Kalk to your water it will strip and precipitate any silicates (diatoms) and most stray heavy metals out of your water.
I have no idea how well Kalk would keep up to a heavy SPS load but currently my maintenance level is about 1/6 of the max that you could safely add in a light/moderately stocked mixed reef.
