35mm needles are ideal for knitting fat bubba wool. I would recommend 25mm for projects where you want to retain a structure i.e. a hat or cushion, and 35mm needles for ‘floppy’ items such as a blanket or scarf.
Whether you use straight or circular needles is up to personal choice, but I have found that the circular needles are more popular due to their compact size and light weight. The wire also allows the weight of the knit to rest on your lap rather than on the end of the needles which with larger projects can cause discomfort for your wrists.
80cm length wire is ideal for snoods and scarves, while we would suggest 120cm for larger projects.