For the entire head, you will need 55DE (60DE for the very thick hair) Double Ended dreads or 80-100SE - Single Ended dreads.
45-50DE for normal hair (70-80SE)
40-45DE - if you want to leave your bangs unbraided.
Mohawk/ Undercut/Shaved Temples - 25-30DE (35DE for thick hair) or 50-60SE dreads.
For the back of the head 5-25DE (5-30SE) - depends on the desired volume.