Guards 10% or less of the force
I not sure Barry if you are familer with Ed Mueller's webpage, he uses a verisan of Volley and Bayonet for gaming the LOA in 6mm (not my fav scale, the Grand Alliance should be fought in the Grand Scale 25/28mm but to each his own
http://homepages.paradise.net.nz/mcnell ... rs_war.htm
Could the Guards have a higher % rate
This what Mr Mueller says
This was, more than any other era I can think of, the heydey of the guards. The proportion of guard to line units in this period is unlike any other I can think of. The unique combination of the old (the 17th century and prior royal and aristocratic perogative) and the new (the modern standing army and the standardized formations and organizations), led to this, I think. The sovereign, be he a king, a duke, a prince, or an elector, would, as a matter of prestige, raise the best, often biggest, regiment--or regiments--in the army, and he would employ the state's resources to ensure that these units were kept at full strength. Instead of raising a bodyguard of horse or of foot which may fight, as in previous wars of the century, now they were raising battalions and cavalry regiments that held position in the lines of battle. Combine this with the relatively small size of the armies of the era, and you have a time period where the guard corps were very much in the thick of things. It's not that there were fewer guards during the WSS and later periods, for instance, but that the ratio of line units to guard units in the larger armies of later periods would make the proportions quite different.
Here's a good example: at the battle of Fleurus, Luxembourg had 34 infantry battalions, among them was the brigade Seguiran, which had 4 battalions of French Guards and 2 battalions of Swiss Guards--if you just count formations, 20 percent of the infantry battalions, roughly, were guard. The French weren't unique in this. Add to the number of formations the fact that guard formations were often larger than their counterpart line formations and that they were usually kept at full strength besides, and you have an idea of the central role these formations could play in the battles of the era. They weren't so much the last reserve of the army as much as they were the heart of it.
The horse of the era in general seemed to have a unique prestige, and many of the units, whether actually "guard" or not, seemed to have been considered elite or "above average" based on the trappings and trimmings of their uniforms (gold hat lace and whantnot, usually a sign of special status). In short, the most obvious case of mounted guards comes from the French, who had a large body of elite horse to draw on. The Maison du Roi represents a body of nearly 2,600 elite cavalrymen by itself; they were brigaded with the Gendarmie, who could easily increase the total to 4,000 elite horse who were committed en masse. This could represent as much as 25 percent of the total cavalry force for an army of 50,000. After 1692, the French converged all their carabinier troops from the line cavalry regiments into massed carabinier brigades, creating yet another class of elite horse. The Williamite army had its elite horse brigade with its Lifeguards (including the Dutch Guard de Paard), and even so called "minor" powers had viable household or elite cavalry contingents.
Would that put the guard element in some cases 20% to 35%