Nice details start at "TROOP ORGANISATION[28]":
http://napoleonic-literature.com/Articles/Rockets/History_of_Rockets.htm
Exact details of how these little imps should perform will depend
upon the game system you use - I have included how I will handle
them in Colonia! if ever encountered:
1. Weights/Sizes
6pdr shell, 9 12 18 24 or 32pdr case shot or shell, 42pdr, 6" 7"
or
8" exploding carcass rockets. Largest field artillery is the 24pdr.
2. Ranges
6pdr - 900yds
9pdr - 1200yds
12pdr - 1500yds
18pdr - 2250yds
24pdr+ 3000yds
3. Organization
Rocketmen have 4 12pdr rockets per horse, organzied into 3 men per
section with an accompanying ammunition horse carrying 18 rounds. An
accompanying wagon carries 60 12pdr rockets.
4. Action
Rockets may be ground fired (as many shots lined up side by side and
lit at same time) or bombarding fire of 6 per turn (3 cannon shot to
20 rocket shots ~ 1:6 ratio).
Ground fire starts out oriented towards the enemy. For every 6
inches roll 1D6 - 1 rocket explodes, 2-3 rocket goes left, 4-5
rocket goes right, and 6 rocket goes straight. If rocket goes
left/right roll 1D6 and this is the corrected line of flight in that
direction (think of shifting the flight path left or right). Reroll
until rocket hits hard target or leaves board. Any figures that make
contact are casualties on 1-3 of D6 with neighbors making morale
check regardless of outcome.
Bombarding fire locates half the distance from the tube to the
target - this is the starting point of the rocket oriented towards
the intended target. Repeat the above steps, however do not roll for
casualties until an explosion is rolled - this is the rocket
impacting.
Ammunition count is key with this weapon - keep track! The basic
concept is to allow the rocket to 'have their voice' and then shut
up. A section can shoot up to its rounds per section in a single
turn using ground volley fire.
6pdr 60 per section; 120 per wagon; bombard fire 12 per turn.
9pdr 45 per section; 90 per wagon; bombard fire 9 per turn.
12pdr 30 per section; 60 per wagon; bombard fire 6 per turn.
18pdr 22 per section; 45 per wagon; bombard fire 3 per turn.
24pdr 15 per section; 30 per wagon; bombard fire 1 per turn.
***********
I think the basic mechanics of this situation is to keep track of rockets available - rockets can have high RoF but you run out quickly!
For Colonia! I would offer:
12pdr Rocket Section consists of NCO(mounted +4 rockets), 2 Bombadiers (mounted +8 rockets), Driver(mounted) and Ammunition horse (+18 rockets).
Ground fired rockets can be done in volleys up to 10 per turn.
Bombardment fired rockets are up to 3 per turn.
Both require initial setup action of either laying out the volley or setting
up the bombardment frame (which would have to be recovered in order to
move).
From firing position measure out 6 inches and roll 1D6:
1 = rocket explodes 1" radius
2-3 = rocket goes left 1D6
4 = rocket goes straight
5-6 = rocket goes right 1D6 inches
Move rocket along new trajectory and reroll (if it hasn't exploded).
Groundfired rockets score a possible hit on 1-3 of D6 for any figure they plow into until they leave the board/explode.
Bombarment fired rockets impact when a 1 is first rolled and as for Groundfire.
Carcass shots (flaming) or exploding heads can be attached (determine fuze burn time prior to shooting).