Going with Kas'im. Raskta had the advantages of BM and teammates against Bane and would have been easily beaten otherwise (the text states that he would have essentially blitzed her had it not been for her BM enhanced speed and reflexes, and that's not even using the primary advantage of the orbalisks). Kas'im was getting dominated by Bane, but largely because Bane was so familiar with his techniques, and when he pulled out something Bane was completely unfamiliar with, he likewise dominated.
Kas'im is more proven in both skill and power, and is strongly implied to be the greatest saber practitioner of that era, whereas Raskta simply came across as the greatest Jedi duelist of the era.