Do both, You already know some algs, keep timing yourself, and start learning the rest, and then time yourself with the new algs you've just learnt until you know full Pll. This way, you practice, and retain the new algs in your memory.
Personally id learn about half then do some timed solves for a couple days. To ensure you can remember each of the algs. Im currently doing this 12/21 PLLs done.