Rubble Stonework
Due to personal preferences, rubble stonework can vary greatly in looks depended on the craftsman. One major factor in the appearance of stonework with todays methods , is the use of cement. I'll give you my though about very irregular shaped stones used on walls.
Before the modern use of cement, stones were laid up in building walls using what amounted to nothing more than clay and in some cases a little lime added. The "mud" was nothing more than a filler vs being the bonding agent of modern mortar. With that in mind, the stones basically held themselfs together. So with the use of cement today, we have removed the need for the stones to self supporting.
A rubble wall section built around 1700's
The natural look of the great castles or the Roman ruins still remains in our minds. Very irregular patterns may be fine for patios, but in my mind, not on walls.
Repointed wall section
Using rubble stone does not leave a opening for complete disorder. You still need to fit the puzzle together in a orderly fashion. Horizonal coarses are fine, and vertical joints must be broken. Corners must be interlocking with the larger more regular shaped stones first. The center of the wall then filled in with the stones of irregular shapes fitted together.
Rebuilt "Root Cellar". Most of the front had fallen down.
It is also appropriate to use the largest stones near the bottom of the wall. For one thing, they may be to heavy to carry up the scaffold, and they do give the look of strength when used at the bottom. Very large stone at the top of the wall makes it look top heavy.
All of this information is useful with dry or wet laid, ashlar or rubble. With these basic ideas, and a little of your own hands on, everything will fit right together. Building with strength in mind, does make things more natural looking.
On your daily travels , look for stonework and see what is most appealing to your eye.