I'm sure everyone is tired of the topic of turkey brining, but I have
a problem. I am set to serve a turkey lunch for 30+ people and want it
to turn out well.

Because I live in Japan and must buy my turkeys from a mail-order
import company, I have little choice about what turkey I get. Last
year, I got natural turkeys. This year, they sent me 9 pound turkeys
injected with an 8% solution of turkey broth and salt (I had to buy
the small ones due to oven size). I normally don't buy this kind of
turkey.

I did a search of previous posts, and the consensus seems to be that
you should only brine non-injected turkeys. However, could I get away
with using a lower concentration of salt? What adjustments should I
make for the size of the birds? I've been brining for so long that
I've forgotten what else I can do to ensure moist, tasty meat (besides
using another kind of meat).

Any help would be appreciated!