I think it boils down to how much stonies you want to keep. You are right around that zone where Ca reactor and dosers start to differentiate as far as which one is better at keeping up with demand. For my 100 gallon, I chose to do Kalk and 2 part, because its what I've done with my nano and it works for me. Only difference is that everthing will be automated. I don't think is a clear cut winner.
I like kalk so I would use it whether I had a reactor or dosers.
Pros of Rx is that once set, it runs itself and less chance of problems. Its also cheaper to run. Cons is initial cost is high and tweaking it may take a lot of time to get just right.
Dosers are great in that they are inexpensive (relatively), eaiser to dial in. Cons is they are more expensive to maintain, and you may have more technical issues (pump burn out, overdose, etc.)
JMHO