Dont forget the 6303 is NABG (non anti blooming gate) and the 8300 ABG, you pay for extra QE, both in money and convienience. Low well depth and NABG can both cause blooming, for different reasons.
Lower dark current is better, it can affect dynamic range.
Ideal image scale nowadays is not so simple to define, Martins
http://www.martinpughastrophotograph...aLRGBFinal.jpg with a 16803 was at 3.5 arc/secs/pixel and it looks great. Horses for courses, image SIZE counts now.
Others say sub 0.6 arcsecs/pix is the go, it depends image size and on how the final full frame view looks.