This is a very late reply to your question about the Takamine GB 7, Garth Brooks model.
I play country, bluegrass and folk music, in local bands in my area. A friend in this group has a large recording studio he built in the finished basement of his large home. We do a lot of recording there.
One of the acoustic guitar players in my group, besides being a Martin and Taylor owner-player, recently bought a GB 7. He is a Garth fan to no end also.
We were suprised how good the GB 7 really is, playing unplugged acousticly and used through an acoustic amp, or PA system.
He uses mainly Martin "SP" Phosphor Bronze in light gauge for finger picking, then will switch to phosphor bronze medium gauge when needed, for heavy chording. He says the sixth string sounds better when using an .054" instead of an .056". To my ear the Martin "SP" light gauge P.B.'s sounds great on the GB 7 playing any way at all.
The only thing he has done with this GB 7, is having a luthier install a quality bone saddle set up, and a bone nut.
His GB 7 does not have the ring of
a Martin HD-28 of course, but the pronounced solid cedar-rosewood tone of this dreadnought does very well.
His recording sessions where he plays straight chording, flat or finger picking, wether plugged or unplugged is just fine.
There is one other Takanine model that may have a slight edge over the GB 7, it is the EF-360SC. It's a bit more expensive, but might be worth the time to find and play one.