Nobody knows it, i dont think everyone tryed it before again..
Alching is the best way to train mage.
And you are almost 97, i suggest you just could use High Alchemy.
You won't loose that much profit?
If u have lunar magic , than complet Dream Mentor Quest and u will be able to cast Humidify. When cast, all items which can hold water (Vials, buckets, waterskins, etc.) in your inventory will fill with water instantly.
So:
1 Astral rune costs 154gp
1 Fire rune costs 10gp
total spend on runes: 164gp
1 Vial costs 67gp
1 Vial of water costs 84gp
Go to bank ---> wear water staff ---> put astral runes and fire runes in your inventory and also 26 Vials --> now cast Humidify --> all of ur Vials will change into Vials of water --> bank them and repeat it