It might not matter but you should start at 0, 1, 2, 3, 4, & 5 for any SSD or Hard drives.
I have my two SSD connected 0 & 1. I have 3 WD 10000 rpm drives connected to 2, 3, & 4
I have a DVD & DVD/rw connected to the last 4 that is by the book it is 0 & 1 again. The last four are standard devices.