How many letters does the top answer for “who was the inspiration for cuthbert calculus in the tintin series” have?

The most common answer is auguste (7 letters).

Crossword clue: who was the inspiration for cuthbert calculus in the tintin series

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

auguste 7 letters otdb

picard 6 letters otdb

One of a sect of Adamites in the fifteenth century; -- so called from one Picard of Flanders. See Adamite.