I'd research this thoroughly before doing it. That being said, it could work. A/B will probably be your best bet. You should not have to thoroughly dry your plants before working with them. Be sure you defat alot, and I'd try to do it using limonene - it gives a "cleaner" extraction (i.e. pulls less junk). Also, assuming you are collecting your phragmites from the wild, try to get your plants from a place that has not been treated with herbicides. You do not need any 2,4-D in your crystals.