There aren't any. The only tier 4 lockbox missions (that aren't from mission items) are Moderate or Bountiful. See torhead: http://www.torhead.com/crew-missions/catg/6/level/33-40/catg/6

Slicers can't, but Artificers can RE augments for archaeology mats. With the low price of augments, it's a pretty cheap way to get mats.

Random number generators are random.

You only get purple mats on crits. Crits are random.

You can't get them off of (at least) anything below Wealthy. I don't know if you can get them off Wealthy missions because I haven't been able to find any artifact level Slicing missions, I assume because everyone who gets them just uses them themselves. Lockbox values for slicing missions work as: Moderate yields always produce white lockboxes Abundant yields normally produce white lockboxes, but produce green lockboxes on crits Bountiful yields always produce green lockboxes Rich yields normally produce green lockboxes, but produce blue lockboxes on crits Prosperous yields normally produce green lockboxes, but produce blue lockboxes on crits I'm not sure about Wealthy yields, since as I said, I haven't been able to get a hold of any purple Slicing missions.

You will get a mission discovery or a schematic on every crit slicing mission, regardless of the mission yield.

I've got results from ~350 slicing missions pre-nerf, and ~50 post-nerf. I've estimated my crit rate at about 15%. I haven't seen any effect of companion affection. I don't have any companions with crit bonuses, so I don't know how effective those are. My suggestion (and what I did) is to spam fast low-level missions to get lots of data for your particular skill.

This isn't true. I've received schematics with Moderate, Abundant, Bountiful, Rich, and Prosperous missions.

I was collecting a substantial amount of data about Slicing returns before the nerf hit, and since then I've been collecting more data to see what changed. Here's what I've figured out: Lockboxes gained from slicing have two properties: a rarity (color) and an item level. The average number of credits gained from a lockbox depends on both of these. The item level of the lockbox is determined entirely by the mission level. (I.e., the class of the lockboxes as described in the mission). Class 1 Lockboxes are item level 10-16, Class 2 18-24, etc. The rarity of the lockbox is determined entirely by the yield of the mission: Moderate: white box Abundant: white boxes, green on crits Bountiful: green box Rich: green box, blue on crits None of this is affected by the nerf. As far as I've been able to determine, the types and qualities of lockboxes received from slicing missions is entirely unchanged. What has been changed are the returns from green (medium) lockboxes. Before the nerf, the quality upgrade from white to green increased the yield about 3-4 fold, which was generally a much larger effect than the effect of Class or item level. A white class 6 lockbox gave around 1700 credits on average, about the same as a green class 3 lockbox. That meant that it was always better to run bountiful and rich missions because you could be assured of getting the much more profitable green boxes. Post-nerf, the quality upgrade from white to green increases the yield about 50% or so. According to the adjusted yields, most missions are still on-average profitable. What they aren't anymore is guaranteed to give you a profit every time you run them. Your four missions that lost you 1000 credits are a product of a random number generator that is balanced by some other guy who gained 1500 credits running missions, but isn't on the forums whining about it. Before the nerf, the most profitable missions were estimated at ~5-6k credits/hr. After the nerf, the most profitable ones are ~1.5 credits/hr. They're also fixed so that higher level missions are generally going to give higher estimated returns, even if they're not Rich/Bountiful missions. Also, slicing mission costs haven't been changed. I've got a list of all of them before the nerf, they're still the same. TL;DR: Slicing is still (on average) profitable. Individual missions are no longer guaranteed to earn credits. Higher level missions are now more profitable than lower level missions.