Read the size range piece by piece
Compare widths and lengths independently.
Check the smallest piece
The label small is relative to the other pieces in that box. Compare the exact width and usable length, not the label. If dimensions are missing, request them before ordering.
Notice where the sizes differ
A set can change length without changing width much. Another set may have a wider gap between its first two pieces. Compare the figures for the same part of each piece.
Treat each piece as an option
There is no requirement to use every piece or move up in size. A larger size is not a goal. Do not force a device or continue if it hurts.