I think you can go ahead and start adding CYA since it is such a pain to have to keep adding chlorine so often but still keep a close eye on your overnight chlorine loss and your CC readings. Also, until that CYA levels starts to register, you will continue to lose chlorine fast and thus will need frequent additions. Once you have a CYA reading of 40-50 and still have no overnight chlorine loss and no greater than a 0.5ppm CC reading, then you should be able to go to testing and adding chlorine in the evenings only.

How are you planning to introduce the CYA to the pool?