Foot line artillery.
Although it's not 100% historical, I use belt variations to make the difference between canons:
- Two belt= 6lb canon
- Rolled blanket= 12 lb canon
- No belt = 10 lb unicorn
- One belt= 20 lb unicorn
Here is the 1805 uniform
The 1808 with new shako and grey pants
And for 1812, difference is the form of the kiwer