Best method for scrolling wgs?

First of all... lets say you have like 500m spare mesos, is this generally enough to turn a profit for scrolling wgs? Or how much mesos is enough to make a profit?

Alright now lets say it is, and if you're looking to make some mesos without merching all day what is the best method to use, statistically? From what I gather this is the price of GFA scrolls (give or take) on Khaini, not sure in other servers but just substitute prices.

So far this is the plan I came up with, do you do anything different?

60% GFA = 7m

7*5 = 35m

first fail = throw away = loss of 7m

first pass, second fail, sell for 2m(?)** = loss of 12m

first pass, second pass, third fail, sell for 4m(?)** = loss of 17m

first pass, second pass, third pass, fourth fail, scroll again (if 6 atk, sell for 10m(?)** = loss of 25m. if 8 atk sell for 40m = profit of 5m)

all pass, sell wg for 130-140m = profit of 95m - 105m

** = I don't know prices of low atk wgs with failed slots, do people still buy them for more or less?