A high quality wind instrument, especially if tied to your knotmeter to produce true wind readings, is a very useful instrument to determine proper sail selection and sail trim. On a boat like the Valiant would also want to be able to tie your wind instruments to your
autopilot to permit self-steering relative to the wind.
Telltales on the shrouds do provide a lot of information but used by themselves they are not terribly accurate since they are influenced by turbulence off of the sails and hull and are also affected by gradiant wind affects. Used in concert with a ''windex'' type masthead fly the shroud mounted teltales are useful for eveluating wind sheer.
Jeff