I use bottom rounds for jerky.
Bottom round/eye of round. I will go to Walmart and they have the yellow tag for quick sale on some cuts of meat. Got 5lbs of eye of round for like $12. Can't got wrong.
I just buy the marinates of the shelf and will add about a 1/4 cup of water or whatever it takes to clean the inside of the bottle out. I also add about 1/4 tsp of prague powder (pink curing salt) per pound of meat. I will partically freeze the meat so it is easier to cut, and trim off all the fat that I can. I cut slices around 1/4" thick. The jerky is softer when it is done and not like you are ripping apart shoe leather the thicker you cut it. I will vac seal 2 lbs at a time and will let it marinate for at least 24 hours and will try and flip it over ever 6+ hours if I remember. Seems anything less than 12 hours to marinate doesn't get through the meat, especially if you throw the slices and marinate into a bag as big clump in the bag.
I will smoke at 150 and usually around 4-6 hours to complete. I will let it cool and vac seal. The reason for the curing salt is some fo the slices will have a little fat on them and if you don't use it, and don't vac seal, it will start to mold after a couple of weeks.