Use whatever grass/leaves you can find at hand. You do have to be a little careful about not using grass/leaves that are too dry. There is a slight possibility of a spark catching when you shoot if they are too dry.
So a handfull of the grass at my feet, or a few leaves from a nearby tree or bush. One wad above the powder, then the ball, and then just enough grass wadding to keep the ball from rolling out the barrel.
Karl Koster has done a bunch of research of original journal entries where they wrote about loading and firing guns. Those entries were very few and far between. One account talked about on person shot by accident with the ball lodging just under the skin on the other side. They cut the skin to get the ball out. But when they cut the skin, the ball and a twisted wad of grass fell out!
But it's more about using wadding to load your gun instead of patching the ball. And loading it in a nammer that could be documented to the 18th century up here in the Great Lakes fur trade area. Karl found the references to using wadding, but not for patching.
Like many things, what and how they did things back then often didn't get written down. So when you do find a refernce, it really does stand out. The next problem then is HOW to interpret it. Did it get written down because it was the normal practice, or because it was so unusual?
Loading blocks are one of those ... questionable ... items. They work great and are very handy. But just how common were they? We know that a few originals have survived, but for what time periods and areas? Most of the well documented surviving examples get dated into the 1800's - that Golden Age of the Kentucky Rifle. But how far back into the 1700's can that be interpreted into?
So grab a small handfull of grass or leaves at hand, roll/twist/ball it up and load your gun. Of course, this is loading a smoothbore. And then there is "palming" your powder to load - pouring your powder charge into your palm to the desired amount and then pouring it down your barrel. THen you don't have to carry a "charger" or measure. With a little practice you can palm a charge to within a couple grains each time. Not MOA target level accuracy, but good enough for normal hunting conditions/ranges.
I can't wait until Karl gets his whole historical gun loading/shooting article published - with all it's original journal entries.
Just my humble thoughts to share. Take them as such.
Mikey - yee ol' grumpy German blacksmith out in the Hinterlands