Ah, thanks, now I have a somewhat better understanding of what you're doing.
1. First things first. Yes there is a free VST/AU delay plugin I can recommend: MUtility, by MeldaProduction. I use the paid version but believe the delay function works exactly the same way in the free version; and it lets you set delay values in samples or mS.
2. I wonder how Dimension instrument sample patches and presets actually relate to the acoustic realities of renditions given by the ensemble players during the Silent Stage recordings. I certainly don't doubt VSL when they tell us that the Dimension instrumentalists played in ensemble while being recorded individually. But also I wouldn't mind betting that VSL's library editors have subsequently tightened up time alignments across the ensemble's recorded samples, so that (a) it's then easier and more predictable for users to apply their own choices of complex post processing, such as humanisation, stretching, envelope manipulation, etc; and (b) the patches are capable of being played in DAWs with very precise temporal discipline if required. I see nothing wrong with such an 'editorial normalisation' approach. That said, I don't suppose VSL would ever describe their competitive tradecraft in detail.
3. I have only the (Sy-zed) Brass 1 library of the Dimension collection but I know what you mean about the 'smallness' of the unprocessed sound of the ensembles. I guess that's probably partly a consequence of editorial tightening - just as in reality, musically very "tight" live ensembles tend to sound somewhat compact acoustically.
4. I applaud your efforts to undo the temporal tightness and acoustic compactness of Dimension Strings. As far as I can see the only thing you would be 'breaking' is that 'editorial normalisation' which one can regard as a technically convenient starting point - ONLY a starting point. Good luck to you!