This indicator purposely does not use "automatic barsback" calculation. The reason is that TS goes through the code to find which setting is appropriate when loading the chart. As this indicator is fairly computing intensive and as the number of bars is known (multiple of 128 bars), it is up to the user to set this parameter properly.
This setting never changes, and can (and should) be saved in an Analysis Group once for all.
By default, the indicator uses a TF multiplier of 1 (128 bars), so only change it to a number over 256 for TFm = 2 or over 384 for TFm = 3. The indicator will not return an error code if there are not enough bars on your chart, and will just cancel calculations.
As a reminder, SD is the Search Depth parameter (0 for default, 1 for refined in most cases), and Fuzzy Neighbourhood allows finding fuzzy pivots, 1 being 'crisp' and the parameter being generally up to 3 or 4 max.