“Pause sync” was basically renamed to “Stop automatic sync”. A large part of why we changed the verbiage is because of what you are talking about, where “pause” connotes that uploads would pause exactly where they are and then continue later (which was not the case).
This also highlights that we need to update our documentation, because it is also confusing the way the description is worded and the image is obviously out of date. I think there was initially a reluctance to use “Stop sync”, although I can’t remember why, exactly. Some odd marketing rationale, most likely
The ability to resume after stopping sync or restarting the client isn’t something that we support right now and would probably take quite a bit of work to implement, but I certainly understand the value of being able to do something like this, so I’ve switched this to a feature request.
On a different note, since you are uploading several large files, you may be able to benefit from some sync parameter tuning, depending on your upload capabilities (and Microsoft tolerances). Here is some additional information on that, if you want to try it out:
Recommended "premium_conf.txt" settings for gigabit connection?