I might do 15 pounds of sausage at a time or, if some of the kids are visiting and they want to take some home, we've been known to do as much as 140 pounds in a morning. Since we prefer to not freeze snack sticks they are the exception in that I might make just 5-7 pounds at a time of them.
As other have already said, pushing snack sticks out of a larger stuffer is very tough on the stuffer and may well be a big part of your breaking stuffers. In fact, many of the manuals for them caution against doing so on a regular basis.
If you have to stuff small diameter casings with a big stuffer the tall narrow stuffers have an easier time of it than the short fat ones. The narrow pressure plate puts a higher PSI pressure on the sausage mix and so long as the mix isn't escaping past the plate's seal it will better fill small casings. To get the same PSI at the stuffer tube a short fat stuffer requires a lot more force on the handle. And a wetter mix may help some in any case.
And grinders suck at filling sausage casings. At best they work well at filling bulk bags. And beware the necessary repeated starting and stopping. Many stuffers are prone to overheating or burning up parts when you do that as the starting load on the motor and gears are several times the operating loads so heat and stress of the repeated starts and stops build up very rapidly. And the gear train takes a beating, too.
If I need to do alot of starting and stopping I use a Buffalo chopper as the belt drive is a lot quieter and softer starting than the gears in the grinder. In fact, I do pretty much all the grinding on large batches with the chopper due to it being smoother, quieter and having less vibration than the grinder does.
If you are going to do a lot of stuffed sausage, especially snack stick sized, consider a hydraulic stuffer. Entry level ones are not a huge jump from the larger two stage commercial quality stuffers and after you learn how to best use them you'll find them to be the bomb.....in a good bomb way.
Just like one tool does it all multi-process welding or woodworking equipment, using one power source for mixing, grinding etc means that you may be starting and stopping several times to do one thing at a time when you could be mixing the first batch while grinding the second batch, etc. And instead of using time to swap bits and pieces and generally only having one person actually usefully employed you can have much smoother workflow with multiple pieces of equipment. Lastly, if something breaks in the grinder you are well and truly screwed.
In my case, my grinder and 14 and 18" Buffalo choppers and all take the same size accessory hub attachments so we can have more than one thing going on during a sausage making binge and be grinding two different coarseness at the same time as needed. And if one ever breaks I can keep working on sausage instead of wondering what to do with all this partially processed meat......
So give strong consideration to having two drive sources on hand.
Best regards,