Envelope filters make me think of Cheech and Chong wandering around Amsterdam ! The only time I have really liked them was on a Bass line I heard by Phish (Im freee....ya de da off Billy Breathless). If you have the pedals already, try em out and see what it sounds like and dont forget, the order the pedals are in between your guitar and amp will make a massive difference to the final sound(like the position of the fuzz on the Hendrix wah).
Cool Beans
S