I don't think there's a need to wait too long for the roots to settle down. It will be stimulated to grow new roots once it is in new substrate and settle. If the fibers are not the right substrate for you the plant may decline. I did read somewhere that they are picky about repotting though so don't disturb the roots too much...I think you need to let the younger pseudobulbs plump up a little first (the third picture), but it's really not that shrivelled, or important to wait.
I repotted mine into the bonsai pot right away when I bought it though the mail in the middle of winter, but I didn't change the substrate, and it shot out tons of roots and growth. The roots are pushing the plant out of the shallow pot right now...I repot all my mail orders right away if I need to