Slurs will almost definitely be followed by the performers, unless they're muck up the bowing completely and even then will only be changed in the most unobtrusive way possible. In general, string players like to have the first beat of the bar on a downbow, so keep that in mind. If there is syncopation, however, then it depends on what feels good (I don't know your piece so I can't say any more specifically, sorry!)
If, for example, you have a long section of quavers that you want staccato or spiccato (like in Mozart...), then you should put in the articulation for one or two bars and then you can say sim. However, if you're repeating it indefinitely, or with very small passages, then you have to put the articulation on every note.
I hope that made sense! If you want, you can send the score to me (but I have only sibelius...) and I can give you more specific information.