The little theorbo sounds great! Concerning your question about "G. re sol": the key denominations in the MS Saizenay use the old hexachord terminology from the modal counterpoint system of the sixtenth century. In this system, the note G could have different functions depending on the context: it can be a Ut when the context is G Major, a Sol when the context is C Major, or a Re when the context is G Minor. The third note after the Re is a Fa, therby resulting in a minor third (tierce mineur). It is weird that this system is used, because there are pieces in this MS in impossible keys from a 16c standpoint, e.g. F# Minor.