If you're looking for pumpkins, use a big muff or a heavy fuzz.
As far as amps go. The best thing to do is experiment as suggested, but instead of just fiddling until you get something somewhat pleasing and writing it down, I suggest you devote an entire saturday to just your amp and guitars, fiddle with them all in different combinations all day long until you know exactly how the amp interacts with different guitars, and how different guitars change the color of your amp. You need to have a solid understanding of what your equipment is capable of, then finding the tone you're looking for specifically becomes a breeze.
Also, I believe I've said this before, but it's useless to go chasing the sounds you hear your favorite artists with on recordings. Those sounds are made with high quality studio equipment and cant be mimiced in your bedroom with any amp, effect, or guitar combination unless you're willing to spend the same cash that the studio spends on its equipment. Most artists' tones are entirely different live then on record, unless they use the exact same equipment they used on recording when they play live, which some actually do, but most don't.
All that matters is that you produce something pleasing to your own ear, it doesn't have to be specifically one thing or another when you're playing live, just something musical. You can worry about shaping a specific tone when you're in the studio, as long as you're at home, just enjoy what your equipment is capable of.