Guadagnini is the most effective designer of violins of his time but Cozio admires Stradivari. Guadagnini is looking for customers. He agrees in 1774 to work almost exclusively for Cozio. The young aristocrat designates his partner as the ultimate successor to Stradivari.
Guadagnini has the mood of a creator and not of an imitator. His new contract is in counter-employment for his designing skill. Cozio goes ahead and buys as early as 1775 to the heirs of Stradivari the violin in a sublime condition which will be later known as the Messiah.
The formal contract is broken in 1777 and Guadagnini can again diversify his production. A violin dated 1778 sold for $ 1.39M including premium by Tarisio on October 17, 2013 is a fine example of his personal art at the time of his better maturity.
Guadagnini continues in parallel to produce imitations of Stradivarius for the use of Cozio. He manages it with some freedom so that his Stradivarius models are not identifiable. These instruments are signed Joannes Baptista Guadagnini Cremonensis fecit Taurini on a label, although his only connection with Cremona is the arrangement with Cozio.
A viola by Guadagnini Cremonensis, dated 1779, is estimated £ 270K for sale by Ingles and Hayday on March 15 in London, lot 63. It is illustrated in the essay published by the auction house.