I agree about the keys being better/easier that the the seaforium charge, but like you said, best prof is all profs. I usually have a couple of these recipes on any toon that I've been farming on/for, and am just looking for a reason to use them/not destroy them. Basically, I'll probably sit on engineering longer than necessary just because it's fun. And I like to blow stuff up. ●~*
The trick is having some extra leather in your bank when you cycle around to engineering. I did it before when things only stacked to 5, 20 or whatever. It should be even easier to do the DMF profession dance with our new huge stack sizes, even with alchemy as a permanent fixture.