I ordered 2 Caravan mouthpieces on trial from classicsax.com (one Large Chamber and one Med Chamber) as recommended. The Large chamber Caravan is noticeably shorter than the medium chamber Caravan. Can anyone account for this difference? Just curious...
The larger chamber piece needs to be shorter to provide correct intonation on modern horns. Remember - the Caravans are designed to be Rascher style pieces for MODERN horns, unlike the Rascher piece (which is a copy of a Buescher).

I'm curious as to where you got the Bilger pieces. They're hard to find these days.