Grand Seiko Straps

I have seen many posts of GS with 3rd party straps (Tuns, Delugs, etc.), but not many with GS straps.

Is it worth buying a GS strap for my Shunbun, or should I go with Tuns?

Does the answer change if I'm trying to maintain a good relationship with the AD in my area? GS boutique, I bought my Shunbun grey market, so no prior relationship, but they still occasionally give me freebies (clothes, loupe, etc.) and invite me to events (GS9, store events, etc.).