In initial alignment we trigger the length feedback to SRM in SRY.  In the last day I've been setting these thresholds to zero so that we aren't triggering, and this has worked fine many times now.  However, when the alignment is poor and the build ups are too low for the triggers we have been using, the WFS don't work well.  I suspect that we've been using the LSC triggers to make sure the alignment is good enough for the WFS to work. 

We could consider a dither alignment instead of WFS, since the length lock seems very robust.  Or, as a first step let's move the threshold to a check that's run before ASC comes on, rather than preventing length locking of the cavity.