How Should I Scroll my Fafnir Angelic Shooter?

Stats not affected by potential include Inner Ability and Character Card (read: card, not deck) bonuses. Stats affected by potential include bonuses from equips, skills, etc.
My method is much more tedious compared to MountLag's (well it's the same concept, his is simplified so you arrive at a conclusion quicker), but it's intuitive and yields a very accurate conclusion as it takes into account exact amounts of att & stat sources.

Okay, assuming I input the numbers in correctly, Scenario 1 is still giving a higher value. 8 ATT scrolls it is.

Attack = your current attack with weapon equipped

(4*5274 + 1198) / (5+4*1.96+.71) = 1645 all stat will double range (1645 all stat is adding around 4869 dex and 2812 str)
(320 + X*1.00) / (1+.00) = 320 + X attack needed to double range, X being the attack on your weapon

Unless X >= 687 the 8 attack scrolls are going to beat the 5 atk 5 all scrolls.

Well the attack is barely going to scrape past 200 at this point (if I use the +5 ATT +5 all stat scrolls), so 8 ATT scrolls seem to be the winner.

Thank you very much [MENTION=8663]user[/MENTION] and [MENTION=10351]MountLag[/MENTION]!