Looking at the magic calculator, it says I need at maximum 6710 wind waves to get to 70 magic, I'd think it good to have a "minimum amount of spells cast" as well as this maximum, as the experience gained doesn't count experience given for hitting any damage.
For example:
Level | Spell | Max Damage of Spell | Minimum Experience Gained | Maximum Experience Gained | Minimum Number to Cast | Maximum Number to Cast |
1 | Wind Strike | 2 | 7.5 | 15.5 | xx | xx |
23 | Wind Bolt | 10 | 26.5 | 66.5 | xx | xx |
41 | Wind Blast | 13 | 38.5 | 90.5 | xx | xx |
And non-combat spells would have "N/A" like they do now.
I think this option would be very valuable, it'd give a users a more accurate look at how many runes they need to buy instead of buying (in my case) 7000 blood runes.
Perhaps an "Approximate Number of Spells to Cast" could be added as well, 1/2 way inbetween minimum and maximum.