I had a alpkit gamma to highlight the arrows but I didn't think they were as reflective as 2011 & 2015.
So it looks like everyone had plenty of illumination and power .
The poor design/size/amount of reflective area of the arrows is an issue that ACP could note for improvement. Perhaps there are French laws which limit the size of 'ad hoc' signs. Twice from Mortagne to Dreux around midnight we missed a turn but the stream of headlights coming back up the hill alerted the de facto group leadership to the miss, so little time lost (not like some of the other poor b*****rs). It also
seemed to me that much of the signage had been erected by 'non-cyclists'. Any route advertised as 'signed', especially one which will be ridden (by some of the field) in the dark, needs a 'warning' sign for any turn off the main road (outside habitation) and if red crosses are to be used, let's make them a decent size, sited so they can be seen AFTER the wrong turn has been made (ie not right on the junction).