So here's the plan...

As it is:
SPWI309.spl calls SPMON1.eff once or twice, calling one or two monsters.
SPMON1.eff calls MonSum01.2da, which has a list of various creatures to be called.
All have three hit dice, as per the BG2 spell description.

How it'll change:
SPWI309.spl is going to call 8 hit dice in total.  8 1HD creatures, or 4 2HD.
It has a 50% chance of calling the 1HD EFF eight times (to summon eight random 1HD).
It has a 50% chance of calling the 2HD EFF four times (to summon four random 2HD).

SPWI407 is MonSum II.  It calls 12 HD.
33% chance for 6 2HD monsters
33% chance for 4 3HD monsters
33% chance for 3 4HD monsters

SPWI504 is MonSum III.  It calls 16 HD.
33% chance for 5 3HD monsters + 1 1HD
33% chance for 4 4HD monsters
33% chance for 3 5HD monsters + 1 1HD

List of Files:
SPWI309.spl
SPMON1.eff
SPMON2.eff
MonSum01.2da (1 HD)
MonSum02.2da (2 HD)

SPWI407.spl
SPMON3.eff
SPMON4.eff
MonSum03.2da (3 HD)
MonSum04.2da (4 HD)

SPWI504.spl
SPMON5.eff
MonSum05.2da (5 HD)

.cre files for 1 through 5 HD monsters.  Argh.
