I am sure that you must be aware that the "700/900 flyin for 50 seat rates" situation no longer applies. As of Jan 1st 2007 all 50 seat CRJ flying rates will increase 1% and 700/900 flying will receive a 5% override with an additional increase of 1% each year until 2010.
So, a 4th year 50 seat RJ Captain (for example) will get paid:
$61.54 x 1.01 = $62.16
if he/she flies a 700/900 their override will equate to:
$62.16 x 1.05 = $65.26 in 2007.
$62.16 x 1.06 = $65.89 in 2008.
$62.16 x 1.07 = $66.51 in 2009.
$62.16 x 1.08 = $67.13 in 2010.
Again, this is pay for 4th year Captains only, and does not take into account standard year longevity increases around 3% per year.
FWIW,
www.airlinepilotcentral.com shows ASA's 4th year 200 Captain rate at $60.00 and a 700 Captain rate at $66.00 (rounded numbers, I'm sure)...