You probably gathered that in my opinion most home processors tend to "over trim" their venison. Venison for grinding will hold together better, have better flavor (my opinion), and yield more pounds if it is not overtrimmed. In the grocery industry I've had several customers over the years refuse to buy Ground Round because it's too lean and "doesn't have the flavor" of Ground Beef or Ground Chuck. The same holds true for vension. Try using your shanks, plate, rib meat, brisket and trim by only removing the excess fat and leaving the silver skin and conncetive tissue and grinding with 25% pork butt and 12 &1/2% Ground Chuck.
As far as aging, I only believe in doing it with the hide on. Skinning and hanging only increases the dehydration.

Trim for grinding the way we do it.

Steakettes from the trim.
Thanks for visiting,
Dave & Ruth
D & R Processing