Use a 10 ml sample when testing chlorine. You don't need the .2 ppm resolution that the 25 ml sample gives. .5 ppm resolution is more than enough!
You will use a lot more reagent

16 drops with a 25 ml sample is only 3.2ppm FC I would not worry about the TA or CH at this point.
Just concentrate on getting enough CYA and keeping the pH between 7.2 and 7.8.
Once you have enough CYA and switch to bleach we can worry about the rest of the water balance if there is a need to. There very well might not be!