For your 60k Bowling Bash: Wear a gr dispell them less dmg you take. If they try to dispell you back, less dmg output for them. Put on gtb, minus 35% reducts from demihuman. Takes a lot of damage in return to deal good damage.
180k asura and 25k-50k tss: Kinda doubtful on this one, how would Tss reach 25k-50k with full reducts. Oh yea deviling? why not use Rays then. You take a little bit more damage, not that it matters you ygg every after one asura anyway. O wait probably it was thana tss, then put a ray with a skoll. Take a little more damage still the same thing, you ygg after every asura. Wait hp can't take asuras with Ray and skoll. Then get higher hp.
But that's not what I'm trying to point out.
Only Assassin Crosses have 8 slots to play with. They could use Valk Rand at the same time do decent damage which can't be done with all classes, since, they could choose to dispell and deal pretty good damage or do really good damage without having the ability to dispell. Lowering the chance for the said class isn't really that big of a thing, specially with their dual wielding capability, so, why not let it happen? It's not disabling the Valk Rand for assassin crosses anyway.