I am making my first log cabin quilt now using 1-1/2" strips.... but it will not be any where near a king size. Did you look at MSQC videos? I bet she uses 2-1/2" strips - which would go much quicker for a king size
here is her curved log cabin, which is on my to do list (some day)
https://www.youtube.com/watch?v=YZTP3h_tIGE