For various reasons I have not year ordered a new E-6 kit, the only route, I gathered, which is available to me without too much hassle.
That's because mixing from ingredients would be a bit too much of a stress at the moment (I have "serious" rolls to process and would like to have a reliable chemical set without making experiments), and because it seems that first developer on his own is basically very difficult to get and I should also mix starter and replenisher every time

So a new kit will be the solution.

Today I was just browsing around APUG looking for information about cross-processing negative film to obtain transparencies.
I already knew that there is some strict relation between E-6 first developer and B&W developer (Rudeofus confirmed it to me in his post in this thread) but I found out today that the two are actually quite similar.

So before I order another kit I might as well ask this question: What about ordering some B&W developer in its stead?
What ingredients should I add to make a "proper" E-6 first developer out of it?
Would the result being equal to a "proper" E-6 first developer or is it a makeshift in any case?

If I managed to use B&W developer that would be fantastic as this is also available in powder or in concentrate which lasts for a long time (such as the Rodinal family) and that would free me from "oxydation anxiety"

I repeat I don't aim at any sort of cross-processing or weird effect. I would like to know if it is possible to have a "proper" E-6 first developer starting from B&W developer and adding maybe a couple ingredients, and if the results are "equal" to the real thing.