That's perfect, although if you don't have automation, which it doesn't look like you do, you might want to rethink getting a Pentair cell. You will only be able to change the output percentage in multiples of 25. 25%, 50%, 75%, or 100%. Those are your only options. If you have automation, you can fine tune it down to 5% intervals I believe.
You might look at the Circupool SWG's from Discount Salt Pool. You would probably want one rated for at least 25,000 gallons. 20K might cut it a little tight, or make you run your pump even longer to produce the amount of chlorine you'll need. Maybe the Circupool Edge 25 for $779, or the RJ 30+ for $1199 might be your best options.
Every model sold by Circupool offers the full warranty on DIY installs, which isn't the case with most other brands.
The install is pretty straight forward especially for your setup. It should be very easy.