How about the OP get a addon that calculates gold you earn from the time you start to the time you finish...
Raw gold,
Greens,
Etc...
AH's Sold..
This is not accurate numbers AT ALL! The guide is useless if it's not true. Your method is the same.
And unless I missed it in reading the original guide as of today @ 12:22PM PST then you forgot the potions of luck. Along with making sure you bring a clothie professioned toon... It increases the amount of Windwool Cloth.