Vincenzo Marra points his finger more or less exactly at a simply difficult question:
“The problem of artificial precision in theories of vagueness: a note on the role of maximal consistency,” Vincenzo Marra, arXiv:1306.4369, June 18, 2013. The author is at Universita degli Studi di Milano, Italy.
(Thanks to investigator K.P. Hart for bringing this to our attention.)