A very useful collection of rare music and much appreciated however it may be useful to inform the veiwer what string parts are missing.ie.
Forster - vla missing / Griffin - vln 1 & 2, vlc missing / Pleyel vln 1 & 2, vlc missing. The remainder of the quartet sets are thankfully complete. Anyway

It would be nice to think that your collection may help in eventually locating the missing parts.