FWIW, if you are used to playing a horn with a sharp 6th partial (as many CC's have), you will consciously or unconsciously pull down that partial. Transferring that to the Schiller would definitely result in a flat 6th partial then. It reminds me of when I started having trouble playing that same G in tune on my bass trombone some years ago. I finally realized that I was intentionally pulling the pitch down on my tuba, and unintentionally transferring that to the trombone where it was not needed.
Good horn for the money. Perfect? NO. But neither are $14,000 horns.
FWIW, I ran into a little of the overprojection problem as well; that is why I switched from a #1 Standard bottom to a #2 Euro bottom. Jury is still out, as I missed two rehearsals this week due to sick kids. Using the large heavyweight funnel Warburton-Neilan completely eliminates that, but is overkill considering the thickness and weight of the horn. The W-N nicely tames an overly live horn, but the Schiller needs just a little something to liven it up since it is heavier than a 'fone.










