@unsound - the many moving parts are gradually coming into better focus. Neither of those 3.6 drivers is in production. The replacement drivers that will serve the 3.6, 3.5, 3 (plus earlier similar) models will be based on the 3.6 drivers, but can allow changes as we re-tool. I am exploring the crossover changes needed to accommodate higher driver and net system impedances. Jim never convinced me that he was correct in his low impedance jag. In fact, it was a significant disagreement between us in the day.
Regarding 'your' 3.5s and to the extent possible for all Renaissance re-issues, I am aiming for a 4 ohm minimum. The CS2 and previous models hung around 6 ohm nominal and 4 ohm minimum and could be driven very happily with a broad range of amps. I'm working back to that baseline.