I really wonder the no spitting factor. Lately I’ve tried snus, as one of my friend uses it to quit smoking (cannot remember the brand, if it even was the same every time), but I find it to generate enough juice to spit away. Enough to be uncomfortable to swallow. Is this somehow a matter of technique? Or a matter of brand choice? Or is it just a thing to get used to?
I don’t have much experience with Snus as I’ve only tried one brand & type as of yet. (soon to be remedied) 
I only know what I’ve read so please chime in if this is not correct. My understanding is there are different ways to manufacture Snus and so some types are more runny than others causing the desire to spit or swallow. I also noticed on the General brand Snus website they give the moisture content for each type and flavor of Snus. White portions of Snus are not sprayed with tobacco “juice” so it has far less moisture content and does not run or runs less. The one Snus I tried was a White portion and it produced very little, if any saliva for me. Regular (black colored) portions of Snus are sprayed with tobacco juice so there’s more moisture in it to begin with.
It also depends on where Snus is placed. The upper part of the mouth has less saliva glands compared to the lower part of the mouth that has more saliva glands. Snus is supposed to be placed in the upper part of the mouth for this reason.
I apologize if I’m being redundant and you already knew this. But it’s so much fun to be able to answer a question for a change I thought I’d take a chance. Plus I’m a big fan of Snus.