Try the pixel modules. 3 LEDs per module. They come with double sided tape on the back. That's what I'll be using and pretty sure that's what others usehttp://i01.i.aliimg.com/wsphoto/v0/920999809_1/promotion-20pcs-string-DC12V-WS2811-LED-full-color-pixel-module-IP68-0-72W.jpg_250x250.jpg
The bullet ones are better if your going to push them through holes. They all have their strong points depending on your prop. Maybe some more info about how they are being mounted and how they will shine would help. The rectangles mentioned are great if they are going to backlight through the coro.
I used the 2811 3led-modules (rectangle) last year on my coro-candles. I used silicon & hotglue to glue them down.
I didnt much like the candles last year so this year I got some new corflute and made some candy-canes and pulled the modules out of old candles and reused them, easy to remove and now much happier with design