Frederick W. Hamilton, Word Study and English Grammar
“ When any question rises it is usually safer to use the long form of comparison in the case of two-syllable adjectives and to use the short form in the case of one-syllable adjectives. The proper use of the long form is one of those niceties of diction which come only with careful observation and with training of the ear and of the literary sense.The word most should never be used, as it often is, in the place of almost. Careless people say "I am most ready" meaning "I am almost, or nearly ready." The phrase "I am most ready," really means "I am in the greatest possible readiness." ”
