Thank you for your considerations folks, much appreciated.
If I may expand a little upon my OP I may provide a few answers to points raised, together with my reasoning thus far.
My system at present is constructed around an ARC Reference 10 pre and Reference 250se mono blocks driving ML CLX Anniversary transducers, so no particular shortage of valve harmonics (nor radiated heat) as is, which in part is one aspect of the DCS way of things that appeals to me whilst still leaving plenty of scope for valve rolling the system should I wish.
I have yet to experience in person the Rossini Player/DAC or Clock, however I have spent quite some time with a good friends Full On Vivaldi stack fronting a very similar system, even down to the same transducers, and am therefore pretty well acquainted with how an Vivaldi Player/DAC combination should work within my own set up.
I would in part concur with Bruce with regard to previous iterations of DCS equipment, however, as has been universally commented upon in recent reviews of the latest generation of DCS gear, I found that they have evolved from that somewhat cold, clinical, almost overly analytical presentation of yore, into an entirely more organic animal, quite palpably believable in the tonality and timbre of instrument and vocal, whilst retaining, if not even improving upon the elements that DCS has always majored on.
It is my understanding that whilst the DCS line currently supports up to 2xDSD that 4xDSD capability is but a firmware update away.
I am still quite undecided as to whether a transport figures large in my future?!?!?? the price difference, not withstanding SACD capability and build quality, in incorporating this functionality, between Rossini and Vivaldi being quite considerable! And a mute point with GG. Somewhat annoyingly, and for the most part, it would seem reviewers and customers comment upon the transport playback on R and V to remain slightly ahead of a rip of the same media.
My goal in the short term will be to audition all three contenders for my ill gotten within my own room/system, in the main to assess how close the additional clock brings the Rossini Player to the Vivaldi Player and DAC at half the cost, but also to ascertain whether the valve presentation of the GG brings its expected organic nature to the system without over egging the thermionic pudding!