How many letters does the top answer for “preceding all others in spatial position” have?

The most common answer is foremost (8 letters).

Crossword clue: preceding all others in spatial position

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

foremost 8 letters wn-def

preceding all others in spatial position

frontmost 9 letters wn-def

preceding all others in spatial position

preceding all others in time 50% similar → premier, premiere