If you want to go the natty route, I suggest raw ash, raw oak, or just birch because all of them break in very well, but the raw ash and oak provide the most grip right when you string it up onto any setup.
I have good suspicion that Musou/Slaydawg/Prime are the best sorta tamas for the GT. Especially for the Specs, the cups develop micro "teeth" (as byproduct of chipping), which grips phenomenal! I have a Musou+Capp which is a lunar beast.
if you got it with a raw ash, then keep it on there. if you got it just ken only, put a raw ash on there. but if you're lookin for paints, I'd suggest cushion clear, musou, sticky af, or KUSA silk paint. any of those play pretty well with GT kens
I just learned that in Japanese language, it would be more correct to say "what tama would fit perfectly". The "dama" spelling/pronunciation is used when the word is paired with another (in this case, "ken-dama"). Kinda off topic, but someone taught me this yesterday, and I've always wondered about the tama/dama distinction so I thought I would share.
Yes, it's "ken" and "tama" separately, but "kendama" as a whole. This phenomenon is called "Rendaku", and i was just reading about it last week!