Too bad you can't switch multiple times in the same Chapter and still get credit. If you could, you could reach 400+ with both by Chapter 3, using just PR.

270 for Argent. Switch to Open. 135 for Argent.
270 for Open. Switch to Argent. 135 for Open.
270 more for Argent. 405 Argent. Switch to Open. 202 for Argent.
270 more for Open. 405 Open.
210 more for Open in Chapter 2, 235 more in Chapter 3. 850 for Open.
Switch to Argent. 425 for Open.
235 for Argent in Chapter 3. 437 for Argent.
End Result: 437 for Argent, 425 for Open.

Oh well.