The most important design aspect of my mod was to make sure that none of Reika's tech trees were short circuited in any way. With a bit of collaboration from both sides, a 'fake' bedrock block that the bedrock breaker with grind into bedrock dust can be added. I wanted to go this route mainly so players aren't being griefed by normal bedrock being unmineable (surrounding a spawn location in bedrock anyone?). Additionally it forces the use of the bedrock breaker which means the tech tree stays intact.
As for special products, Ex Nihilo "dust" in my mind was something that you could dissolve in water to make a slurry... much like the second stage of the extractor. this would force both the highest speed (stage 3) and power (stage 4) requirements of the extractor, though only half the torque. The trade off is that you're losing the ore multiplier of the first and second stage, which in my mind makes up for the fact that the requirements are marginally easier. But you would get the special outputs this way without any fancy configs for users to tinker with (i.e. outside the modpack).