Here's my thoughts, for what they're worth on the alto and bari pieces (I don't play sop often enough for my opinion to be worth giving):
Bari (usual setup - mk6 low a bari; RPC 115b; RJS 3s): a nice, easily controllable, warm sound. Intonation was fine across all registers from the moment I put it on. Particularly rich sound at the top end (quite a feat on Bari). If I was doing lots of smaller combo/purely acoustic work on bari, I'd have no qualms about using this, however I feel that I'd struggle on it in my big band. I prefer my RPC as its more versatile; having the baffle to push against means I can really drive it when I want to, or I can open up the throat and oral cavity to get things nice and smoooooth. I felt that the Absolute lacked this versatility - in my hands at least.
Alto - usual setup is a 1953 SBA, Morgan fry 6 ebonite and Alexander NY 3s.
Metal: I loved this mouthpiece, it was so much fun...a bit like my old mk1 Mini Cooper it was playful, agile, lively and a little bit wayward on occasion. The tone was brighter than my Morgan Fry, though not lacking a strong core like some bright pieces I've tried over the years. The altissimo register was superb tonally and it was easier than almost any other mouthpiece I've played to get this register sounding like a natural extension to the normal range rather than a naff gimmick. The only negative to this for me was with regard to intonation around the top of the stave, up as far as palm d...this is the wayward part I referred to. Admittedly it probably wouldn't be the case on a modern horn but on my 63 year old Selmer, it was a battle.
Ebonite: this is another very good mouthpiece and perhaps a more fair comparison with my Morgan Fry. Very free blowing, easily controllable mouthpiece with an immediately pleasing tone which is in the direction of the classic alto tones (Meyer...ish). It has a warm core with a nice bit of buzz when required and likes being pushed. Excellent dynamic range and intonation.
These are all excellently made mouthpieces with the workmanship on the table, tip and rails clearly of a high standard. I'm happy with my current mouthpieces at the moment but if I was in the market, the absolute range would definitely warrant consideration.
Thanks for the opportunity to try these, now to organise their return.