Let's say you have a magic system similar to Lenga in your Action! System game. Using magic adds three new attributes, spells are skill rolls based on one of those three attributes. Like other attributes in the Action! System, there is an attribute that represent raw power, magic control, and magical defense.
In Lenga you would roll 3d6 and add the attribute and skill to the roll For example, let's say a spell that turns a pound of lead into a pound of gold has a TN of 30. This spell relies on the control attribute which for your character is 6. Your skill with this spell is an 8. Rolling attribute (6) + skill (8) + 3d6, the total needs to meet or exceed 30. In other words, you need to roll a 16 or better. Instead of using 3d6, consider the following to add to the attribute + skill roll:
Roll nine dice and arrange them in a 3 X 3 square. You don't get time to pick and choose, just quickly group them. You have the possibility to get up to 8 successes. How you determine those successes will change depending on the attribute related to the spell. Consider the dice positions below:
1 2 3
4 5 6
7 8 9
If the power attribute was the base of the spell, your eight chances would be determined by eight lines. Namely: 123, 456, 789, 147, 258, 369, 159, 357.
If the control attribute is the base of the spell, your eight chances would be determined by corners. Namely: 412, 236, 698, 874, 426, 842, 684, 268.
If the defense attribute is key, total all nine dice and divide by three. Round up the result to the next whole number. Yes, this gives defensive spells a slight advantage, but it's not as much as you would think.
The number of successes will determine how many dice are rolled to add to the effect. I haven't worked out exactly how many successes equals a number of dice, but let's say that:
1-2 Successes yields One Effect Die
3-5 Successes yield Two Effect Dice
6-7 Successes yield Three Effect Dice
8 Successes yield Four Effect Dice
Using the same example spell above, your attribute is 6, your skill is 8, you roll nine dice in this pattern
3 4 2
5 1 6
2 6 5
Because it is an aptitude based spell, use the corners to determine the 8 rolls added to your attribute + skill. The results are:
5+3+4 or 12
4+2+6 or 12
6+5+6 or 17
6+2+5 or 13
5+4+6 or 15
6+5+4 or 15
6+6+5 or 17
4+6+6 or 16
Since you need results of 16 or greater, you have three successes. This means you get two extra dice for the spell effect.
Give it a shot.