A summary would be awesome - I appreciate the amount of work and details that went into this, but a list of what worked and didn't would be a great start - interested readers could then dive into details
The standard stuff is L-Theanine + Caffeine. For cognitive enhancement any of the "racetams" are considered proven, and you branch out into untested army drugs when you take modafinil.
I've tried each of these and stick with L-Theanine and Caffeine daily. Piracetam had no visible effect on me. Modafinil got me through 36 to 50 hour work days straight, at crunch time when deadlines were needed for an old job. Work was probably at about 60% of its best at the time – easy to get into the zone but also not quite my best. I know it's not healthy but I was also curious and happy to try it out of personal curiosity. YMMV :)
What on earth are you talking about? Modafinil is very much _not_ an "untested army drug". It's pretty well-studied, approved for use by the FDA, and available for sale (with prescription) under multiple names in the US, and by prescription with no other legal restrictions in most other countries. It has a freaking WebMD page[1]!
[1] http://www.webmd.com/drugs/2/drug-16964/provigil-oral/detail...
Learned something new today.