For my latest hat-related project, I used a wool felt body/cone from Jedrzejko (Poland) in the Dark Turquoise colorway. Mistress Milesent Vibert inspired me to try needle felting after she used the technique on a hat blank-turned-bycocket created during the Gulf War Widows experiment earlier this year. She briefly explained the technique then recommended a beginner set from Grey Fox Felting (36T, 38T and 40T) with a Needle Felt Support Block.
I initially tried needle felting with a more fine skein of embroidery-weight wool which didn't work as well as I had hoped. I moved on to a yarn weight in ivory/white (which I think I picked up at Pennsic for nalbinding.) I wanted to add additional color, so I checked my available stock of yarn that has aged greater than 10 years and found the soft pink color to accent in a two ply merino wool.
Overall, I feel this is a beginner project. It's even easier if you have a background in scribal, since my inspiration/design came from an illumination. I spent a series of lunch breaks laying out the spiral pattern(s) with tailor's chalk, then came back with the 40T ultra-fine needle to tack down the yarn. I doubled back when I was satisfied with the placement to more firmly attach the yarn.
