For the second attempt, I got ambitious and did 12 lbs (9 pork shoulder, 4 belly), split across 3 types. Hey, if you're gonna make sausage, make SAUSAGE, right? Also, I got a vertical stuffer that made stuffing a breeze compared to the Kitchenaid mixer.

Al Pastor - ground dried chilies (guajillo and ancho), achiote powder, garlic, onion, cilantro, Mexican oregano, pineapple juice.
Lao Sausage (Ryan Farr book) - bacon, mint, basil, lemongrass, cilantro, galangal, shallot, garlic, kaffir lime leaves, fish sauce.
Cheddar Jalapeño - extra sharp cheddar, jalapenos, garlic, onion, apple cider vinegar.

While the flavors were good, the texture was dry and crumbly. I used the smallest grind plate this time, not sure if that made any difference. After doing some research, I've narrowed my problems down to the following possibilities.

Primary bind not achieved. Did not mix well enough, only for about 2 minutes by hand. Also, probably didn't do a good job of keeping it cold.

Next time, refrigerate all equipment parts including stuffer. Refrigerate meat after ever step. Try to keep meat below 38F. Use the stand mixer with paddle attachment at lowest speed for one minute, add the liquid, then mix at a higher speed for another minute. Meat should stick to the sides and have a furry appearance.

Sausages burst on the grill leaking all of the juices. This was due to a poor job making links and cooking them too hot. I made the links too fat again and twisted them too close to each other not creating enough separation. Some of them opened up when I cut the links apart. Was too lazy to re-stuff them. Next time, leave a few inches of extra casing at the end and keep it untied. Also, when making links pinch and squeeze the meat to create better separation for cutting.

I cooked them on a charcoal grill over direct high heat. The leaking juices started a grease fire so they got extra hot. Next time, cook over indirect (till the reach 150F) and make sure sausages are properly enclosed.

Going forward, I think I'll practice with smaller batches until I get the hang of it all.