[Demonic viscera]

I play both 6 and 7 string guitars , the sevens being in standard and the sixes being all different. sevens are a good guitar to get for low tunings because the actual scale length of the guitar is set for the additional string. This means less chance of fret buzz at low tunnings if any. it works the same as a six from e to e but with a low b below. The downside for this is that in order to get c you would have to tune up the b wich is not recomended. My band plays in b so it is no problem.

however, buying a seven is a bit far fetched and you would have to learn to adjust to the extra string. that being said, i have a neck through mocking bird with 13 guage strings on it. Luckily enough i have had no prtoblems with the action. The thicker jazz strings will give you the wound g string(ha ha) wich will compensate for tonality loss on the thinner set. The tunning of course is in b. The downside of thicker strings is they are harder to play, but being tuned down just makes them thicker to play since tension is droped from tuning. Besdides, a litle bit of batle for your ingers would only make you tighter.

another option is the baritone six string. With the scale length set for lower tunnings, they make putting on a thicker set a cinch.

I don't know what you prefer but i use 11 guage strings on my standard tuned guitars.