The 1792 Regulations only specify 3 officers per company (Formation of the Battalion Page 66). No ranks are given in that section but further down it mentions the Captains commanding the companies.
On Page 63 there is a section on Formation of the Company. This says:
When the company is singly formed, the captain is on the right, and the ensign on the left, of the front rank, each covered by a sergeant in the rear rank. The lieutenant is in the rear, as also the drummer and pioneer in a fourth rank, at three paces distance.
The left of the front rank of each sub-division is marked by a corporal. -The right of the left sub-division may be marked by the other corporal.
Where necessary, the places of absent officers may be supplied by sergeants, those of sergeants by corporals, and those of corporals by intelligent men.
When the company is to join others, and the battalion, or part of it, to be formed; the ensign and his covering sergeant quit the flank, and fall into the fourth rank, until otherwise placed.
[Note the reference to fourth rank is because the regulations assume the main body is in three ranks, not two, the latter being the invariable practice. The reference to part of a battalion normally arises when operating by half battalion wings, but could also refer to a detachment of two or three companies for a particular purpose].
At some later stage I think that a fourth officer (either another lieutenant or another ensign) were authorised per company. This would presumably appear in regimental establishments, rather than drill regulations.
I do not have a copy of the various establishments, which changed several times during the wars, but if anyone can point me in the correct direction to obtain copies of these I would be very grateful.