Game on. I will take odds on that Barrelchief as I was auditioning the Rowland 201's, 501's, and the 302 (heard it, wasn't in my price range) with the Synergy IIi before I stumbled upon the H2o's.
With that said, the Rowland 201's and 501's didn't compare to the 302 (obviously) and neither did the 201's or 501's compare to the H2o standard stereo IMHO. FWIW I think the 201's sounded better in the mids than the 501's, however the 501's did appear to have better control. The 302 is a different animal than either the 201 or 501. I was told by a Rowland rep that the 201 is 85-90% of the sound of the 302. I will have to respectfully disagree. However, perhaps the refinement, etc. is in that last 10-15%... it just didn't sound that close to me.
I would contact Henry and see if he has a *broken in* pair of Signature Mono's you can audition. Make sure he is aware you want a broken in pair, as I can tell you now, the sound change is drastic between a new unit and one fully broken in, especially in the mids being fleshed out and liquid as well as the air on the top end.
I haven't had the pleasure to compare the Sig H2o Monos to the 302, however if my memory serves me correct, and there is no impedance mismatch between the Synergy IIi preamp and the H2o's I think you will be pleasantly suprised.
Are you also looking to downsize on your preamp, as that is a very good preamp...