"Understanding the role of Grenadiers" Topic

While Voltigeurs as light infantry have a clear role in napoleonic warfare (or better: my understanding of it), I struggle with the job description of a grenadier: he forms the elite of the line infantry, but what about a situation in which the grenadier company is detached? Specifically how much do they work together with the voltigeurs? Do they form a reserve or kind of backbone? Or do grenadiers also skirmish by themselves?

Well, a lot of grenadiers COULD skirmish, especially in the French Army. They were veteran troops, after all. But I think that misses the point. Grenadiers are assault troops--the men you want to storm the barricade--and in a lot of armies the standing grenadier battalions spearhead an attack, or maintain cohesion in defeats. As for those French-style battalions with elite companies in line battalions, you only strip both elites when the center companies are completely useless and left in garrison somewhere, and then you usually form separate converged battalions. I don't think I can recall more than about three instances in which there were battalions containing both lights and grenadiers stripped from their battalions.

Can you expand on the question a little? What are you looking for in miniature wargaming terms?

I want to play on a very small scale starting with three or four bataillons. I want to detach my voltigeurs and grenadiers (as "detachments" in Valour&Fortitude) and let them do the main work together with light cavalry and horse artillery. (Kind of re-enacting the so called little war/kleiner Krieg).
As I use a 6 company-structure sending of the Voltigeurs would hurt my sense of geometrics in the remaining part of the bataillon. So I would prefer to send two companies into the skirmish line. In the WSS, WAS and SYW the grenadiers were used as a screen, the "piquet" afair were introduced later into this concept, so did the grenadiers actually lose that task? And would only voltigeurs screen assault?

With just three or four battalions, combining your grenadiers into separate reserve would make a lot of sense.

Did grenadiers really screen assaults in the WSS, WAS and SYW? I don't recall reading any acconut sof that.

No, they were used to screen the deployment of a bataillon, not an assault, as this would have been done in line.