On high MP disc maintenance for xbow users that lack +max disc on gear:
either get one with life steal and suffer a loss in dps or do as i do:
nightstalker - chance on 1 disc per crit
perfectionist - -10% on casting disc spells
preparation -
focussed mind - this rune on preparation artificially gives you 15 more disc, doesn't seem much, but as the cooldown passes, you gain disc by keep shooting AND from disc over time
this is especially helpfull when you fight in tight corners like in keep depths, where some mobs have 3x damage affix: molten, plagued, arcane, frozen, mortar where they controll the floor with themselves and their AoE dmg stuff flying around
it's then sometimes not enough to perma-shadowpower and you might need to create distance by e.g. vaulting to the next room(s), nice bonus affix is when they wall you so you either die or vault through all that crap flying around

this requires restrained usage of disc though on high mp...
i plan to get higher crit chance and get rid of preparation alltogether so i have room for either a nuke or a crowd controller, which skills have the best synergy with nightstalker?