Do NOT use the Hayward -- it's a major flow restriction. I've got a picture somewhere - the primary port on that thing won't pass a quarter!

If you are going to install a trichlor feeder, use the Rainbow 320:
Pentair Rainbow 320 Automatic Chlorine/Bromine In-Line Pool and Spa Feeder

However, I am NOT recommending that you do so; I don't know enough about your pool. You really ought to fill out the Pool Chart so we will:
Pool Chart Entry Form