www.sparklersonline.com

We ordered their 20" sparkler and we had around 250 guests.  It worked perfectly.  I have been to lots of weddings with sparkler exits.  I would highly recommend not using the tiny cheap ones you get at the firework stand.  They don't burn nearly long enough to get the effect you want.  I also didn't want to shell out over $1 apiece to get the "36.  I thought the 20" was perfect.  sparklersonline was easy, shipping was fine, very smooth.
A+