If you're not familiar with Tremelos, they're pretty easy to learn to use. The function basically like a Chorus pedal on steroids. I've got one by DOD that sounds great, especially when playing a Strat set up semi-clean with the neck pickup. I think Stevie's choice was a Roto-Vibe pedal ... but I may be wrong.
You can pick a Tremelo pedal up for under a $100.00 and play around and experiment to get that "Stevie" sound ......
