I haven't tried curlers, but here's my trick for nice defined curls that are curlier than my usual 2a-3a wavycurls:
Squeeze water out of my hair with a sarong after a shower and put in gels. Then I twist the curls around one or two fingers, gently, and pin them. I put my fingers at the scalp and with my other hand, wrap the hair around them and slide the pin in. This makes little circles of hair all over my head. Around my face where they are shorter and finer I use one finger, everywhere else usually two. I spray with spray gel and let them sit for a few minutes, then use a diffuser on them for about 15 minutes on the lowest setting. De-pin, don't touch nuthin, diffuse again until about 80% dry, and for lots of body I do this part upside down. Spritz again with spray gel and done. I get soft, defined curls that last all day.
I tried this trick at night once, left the pins in overnight and let my hair dry naturally. Can we say "poodle?" Not good.
One of my housemates bought soft curlers to wear overnight and I might try that to see if I get less poodle. I'll let you know how it goes!