(V) Is there then something implied really special all the centuries about Carrera year 1617 Centaur(bn) and Champion(rn), so not subject to time-honoured design considerations?  How could that be so if the types, unlike R-N-B-K-Q-P, figure in less than 0.5% the space of Chess tracts, histories and monographs?  Even mediaeval Alfil and Ferz get mentioned more in passing reference.  It appears the literature has plenty of catching up to start doing on nuance of B+N and R+N, a real gaping momentary lapse.  For instant starter, how to get maximum potential advantage if opening '1 Knight g1-f3... 2 Elephant drop -g1...'?  Will this '2 Elephant -g1' become standard? Think thump trunk-derivation instead, and Castle/00 (!) may become the favoured modern move to open Elephant(rn) line of attack. That scenario would lead up to '5 Elephant-h1...' where the vacated rook sat before the Castle. There are superficially 8 possibilities in the back rank, but really 10 or 12 when Castling is considered.  'Ten' possibilities because King and Rook must themselves go to an otherwise impossible square with subsequent immediate plant of the off-board Hawk or of the Elephant, upon the Rook overstep, at either vacated King's 'e1' or Rook's 'a1/h1' next turn.  All the contingencies cry for complete analysation where none exists.  How and when to vacate and to drop them, the Hawk and Elephant, are virgin territory.
Besides, S-Chesses in their cautious original serial drop technique open the door to other related, interesting but different from each other piece-types to be used and introduced just by designing what cvers call 'subvariants'.  The same conservative near-rank same-side drop can be used for other pairs than those ancient upstart, awkward rn-bn. If Centaur and Champion turn out again not to be the cat's mieow, there are many other related pairs to try in their place: Cannon and Canon, Duke and Cavalier(Renaissance Chess), Falcon and Hunter (Schultz's year 1943 Hunter-Falcon), Left Schizzy and Right Schizzy(Schizophrenic), Bent Hero and Shaman. Examples only all of the foregoing, because the list since year 2000 has to reach 100 or even 200 of intriguing, connected pairs of p-ts clearly delineated from each other.  Extending the S-Chess concept to warrantable subvariants brings them on board in familiar environment for trial one by one as two only each new CV under S-Chesses 8x8 -- rather than the usual paired fixed pre-placement approach 8- or 10- or 12-wide.