I'd definitely dose 2part over having a kalk and calcium reactor.
I used kalk and a calcium reactor for years and i much prefer 2part. First of all, it's much cheaper to start. Secondly, it's much easier to fine tune. Dealing with the bubble count and water flow on a calcium reactor can be a bit of a crapshoot. With 2part, there's no guessing. My numbers stay exact every time I check my water.
Making 2part is incredibly easy and if you get the 3 gallon jugs, you rarely have to refill them. IMO it's much easier than taking apart a kalk or calcium reactor to refill. If you had a 300+ gallon aquarium, i'd say go with a calcium reactor. But since you have a reasonable sized tank, definitely go 2part.
Lastly, it's an interesting choice that you added a yellow tang first. I wonder if he'll be aggressive to other fish mates. My yellow tang is pretty territorial. Once established, I'm curious if he'll be a bit rough on any new fish you add. At the very least, I hope you don't plan on adding another tang, because it will probably turn into WWIII. Best of luck.