- You want a buriza with 14+ freeze, 60% or more piercing, and a socket with an amethyst for LoH - this is huge for his survivability on high mp levels.
- An Azkaranth ammy with at least 3% freeze (preferably 4.5%) and improved attack speed.
- Two 9% ias rings with tons of vit on them, preferably with sockets for even more vit gems.
- A follower token with 300+ vit, armor/strength, all resists, and more LoH. Don't worry about dex.
Granted this can be expensive to set up, but generally people are geared well enough by now where this gear should easily be easily affordable. You'd be amazed how much more efficient your runs get - even with just a difference in 1.3 - 1.44 ias for Scoundrel.
Also - don't bother activating Scoundrel's first 2 skills, just active his crit bonuses and multishot so he's ALWAYS freezing enemies, not wasting shots slowing them or hiding because he's low on health (that's why you have vit gems and LoH stacked on him). So much effort is undertaken by the community in hitting breakpoints, having just the right gear/build/etc - and yet the majority of your Scoundrel's are complete junk.