Only to a point. Overfilled ( more properly called too tight) will have draw problems. Too loose and the tobacco will not be "Properly acquainted with one another" and will require frequent relights. Kinda like a camp fire; Spread out the kindling so its not touching each other or the larger pieces of wood and it will not support combustion. Before I had a mold I rolled them too loose and that's the problem I struggled with.