I have used an electric smoker for the past 15 years for brisket, ribs, pork butt , fish, and veggies.
This last week I made my first ever batch of summer sausage following the recipe and and supplies from Walton’s. This batch was 20 pounds when finished. Fantastic appearance and taste, I could not be more pleased.
Next up is a 25 pound batch of bulk breakfast sausage to go into 2 pound bags.
I started making mayo about a year ago. I have used both unpasteurized and pasteurized eggs. I cannot speak to your basic questions but I get longer shelf life than a couple of days. I now use only pasteurized eggs and they are very easy to prepare. I use my sous vide water circulator for quick and positive temperature control for the pasteurizing process. My go to recipe uses only eggs, canola oil, fruit vinegar, and salt. I really enjoy the fresh taste of homemade mayo and now cannot tolerate the commercial brand that I thought was great stuff. Made more work for me but it is worth it.
Cali sausage guy
I am older than dirt but I am a newbie at making sausage. This is what my first attempt at packaging bulk sausage looks like. I used three pork butts in the batch and I had 23 pounds net product to go into the freezer. Most of that will be gifted to my Daughter and Grandson + great grandkiddos. 
strenkarosa
I have only made one batch of summer sausage also using an electric smoker. Your smoke/cook time seems to me to be excessively long. Did you follow the smoking/temperature steps recommended by Walton? What was the temperature of your sausages when you placed them in your smoker? My intent is to not be critical of your results but to begin an analysis of things that could have impacted your result. I am an amateur sausage maker with only a few batches made. I will follow along to see what we all can learn here.