Both these sound good IMO, but how is Vista + Vista set up?
To
@LiamHKW, if you' re still looking into this or looking for more, CSS is also an alternative many of this forum's users (including me) find useful.
It may also be worth taking an extra look (since you mention 'mainly violins and celli') at those libraries which can be bought one section at a time, like Performance Samples Con Moto (both Violins A and B are very useful), and Spitfires ARO Cellos and 1st Violins 1 – especially right now, due to the campaign: €244/€149 for the Cellos and €359/€199 for the 1st Violins. (I don't have any personal experience with the Abbey Road libraries.)
Among the examples posted in this thread, AR combined with Vista sticks out as one of the best solutions.
Vista II will probably also be a brilliant alternative when it's released, but I don't know if it will be possible to buy one section at a time.