Hi Daniel. I suggest that in addition to the wood crossovers you're looking at, you should also consider carbon fiber crossover offerings from Rainsong, Emerald (allows customizations) and Blackbird. As you may know, CF is immune to humidity issues and holds tuning remarkably. To my recollection, acoustic volume has never been stated as an issue with CF crossovers. I don't know your budget, but CFs are quality instruments and are not cheap. If you want to know more, I further suggest that you spend some time in the AGF carbon fiber subforum. There are a few very knowledgeable members there who are nylon/crossover aficionados (EvanB, Tom2, sirwhale, in particular). There are a number threads that discuss CF crossovers. Good luck in your hunt.
Here's a link to one detailed thread:
http://www.acousticguitarforum.com/f...d.php?t=469133