This is a very interesting question that has several answers: practical, modern, professional & historical. The "griffen" element is subjective, of course.
1. Professional. As a professional, you need several theorbos. For my work, I require at least four. Therefore, the theorbo in G at 465 doubles of course as a theorbo in A at 415, and so on. If you play multiple services per day, you can't tune up and down all day, every day, you will always be out of tune. If you play out of tune all the time. someone will notice; at music festivals, I often play at three pitches per day. If you play in ensembles that are picky about voice leading and parallels, you will require at least one single reentrant tuning instrument, and for a greater percentage of music an instrument in G will be better: better chords, fewer parallels. I would say, based on playing at least a few thousand pieces, that the ratio is about 65-35. YMMV. Maybe you only play in A major :). There are definitely groups out there that will not rehire someone who plays bad bass crossings and parallels, but it is not the majority, it is definitely a consideration. They may also appreciate it on a subconcious level, that some of the chords sound strange. If you don't play every day in different groups, this is not for you. 2. Practical. If you have only one theorbo, you must make some choices. If you play mainly solo music, tune your instrument where it sounds the best, plain and simple. A lot of people play their instrument at the wrong pitch. Keep marked packs of strings for each tuning you will need, and only change the fretted strings. By changing the strings you maintain the tension and the stability of the instrument. In a tone transposing scenario, keep the lowest long string at F, and read it as a G in the other tuning. For half step scenarios, it is marginally better to leave the basses where they are for short term, or tune DOWN a half step. If you mainly play continuo, G tuning is better, marginally, as per comments above. 3. Modern practice is different from historical practice. Modern practice follows the guitar. Evaluate the situation depending on the types pf ensembles you play in. For example, if you play Opera, you will not be allowed to tune as often as you would need to, choose your strings accordingly for the theorbo. You may play with modern instruments as well. Modern baroque ensembles use wound strings on the violins, violas, and cellos: you cannot realistically compete with that in a pure historical setup. I have never seen an ensemble or orchestra of any size play in pure historical setup--strings, bows, bridges & bassbars--maybe they are out there, I have not seen it. 4. Historical: this goes to training. If you are trained in a transposing system, which the musicians of the Ren & Bar were, then there is effectively no difference between G, A, F and so on. They look the same. If you want to play more historically, you have to start with this system. There are no shortcuts, except a modified Alphabeta, which I often use, and then it comes down to preference. You can be "Even Keyed" "Favor A, play G" "Favor G play A". I'm somewhere in between Favor G and Even Keyed. As far as the historical record goes, it is clear that they had the G tuning and the A tuning and other tunings as well, that they were pretty Even Keyed, and that the A tuning gives more sound in DOUBLE reentrant, for obvious reasons, and so is better for solo music, or music in which you play often an octave lower to avoid bad crossings, like a Quint bass. Thinking like a Quint is important. The very early sources show a leaning towards G but that is deceptive: there are not enough sources and of course, G looks like A if you are a transposer. Nonetheless, G makes an early showing, and modern practice clearly follows the guitar. A nice compromise is to have a larger theorbo in G, single reentrant, 415 for continuo and a smaller theorbo in A, 415, double reentrant for solo. The A instrument doubles as a G instrument at the 465 pitch. Keep a set of strings handy for 440. This mirrors Ren practice of the lute in G and A. Coincidence? Add a 440 instrument for Vespers and Modern Opera and an archlute and you have most of it covered. One more theorbo and you are there....almost. dt To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
