Low cost index does not always equate to the best economy. If its going to slow you down 40 mins on a bkk fra then you must be armed with "all" the information. ie what is your airlines "direct operating" cost per hr and reserve for overhaul costs? Good luck getting this information from your company as most of the time it's a closely guarded secret. They don't want you as Johnny pilot to know.
I haven't understood this point of yours. What you have stated above is the whole reason that the cost index on which flights operate isn't always 0. It's a balance between fuel costs and time related costs, and it isn't a secret.
on topic:
There's a fuel economy card issued to the pilots in the company for which I work. I can't find it on an open source at the moment, so I can't post it. If I do, I'll get back here. Regardless, pilots working with an airline have plenty of company-issued material to save fuel (it's in their own best interest).