I just do not buy your nice story my friend: 100 greens to get one 25 years old player from 120 to 140%. Pure joke! It took at the very least 50 greens each to pump up my 5 18-years old FT from 5 to 6 stars.
And even if you could find one by luck (there is only one Messi after all!!), you'd need to do that 12 or 13 times to get a 140% team. Which makes almost 1500 packs. Easy as you said... Just tell us you are tanking or buying greens.