@byrdeus - two things to pay attention to include:
a) the fat content of the beans themselves
b) the recipe
The fat content of beans can range from 47-53% or thereabout. The same recipe (70% cocoa and 30% sugar) can have very different viscosities based on the native fat content of the beans. In general, I advocate adding enough cocoa butter to make your life easy in depositing and molding, and to achieve a good mouthfeel.
The kind of sugar and how/when it's added will also have an effect. In general, most makers I know advocate waiting several hours after the liquor has reached a fine paste before starting to add sugar. Some sugars, especially coconut blossom sugars, have a high moisture content that will affect viscosity. Crystal size, moisture content, how/when added will all have an impact on final viscosity, as will the particle size distribution of the chocolate.