I only just ordered two army packs from the range Wars of the Sun King, which haven't even arrived yet, and I'm already thinking ahead (I've been buying wargaming stuff like crazy these last few months, I guess it's because I dread what could happen after brexit):

At some point I'll need grenadiers as well, as these aren't included in the army packs (I ordered a Dutch and a French army). I think I can use 'WSS04 - Grenadiers - Short Mitre' for the Dutch, but what about the French? I've even read somewhere that they apparently didn't bother with a mitres and just folded up the sides of their hats...

Any experts on the subject here? I'd appreciate your input.

French grenadiers were more or less identical to the ordinary infantry, they had a bag for the ir grenades and similar minor differences. They could fold up the sides of their hats so did ordinary soldiers. 

I would just use the standard infantry.

Nick has got it spot on. 

Thnx all!