Nickel movement is really really nice, but there are many evident flaws on silix's GMTII:
horrible conical case rehaut date window too big mag on crystal far to the right GMT hand not so accurate not perfect CGs...
IMHO the best way regarding GMTII is to contact bklm1234, he offers GMTII "noob version" from $300 to $400 range with great case rehaut with some custom mods (trimmed CG's, improved bezel and inserts...).
Otherwise, Trustytime & Perfectclones's GMTII "retro edition" looks nice too.
Anyway, read this, please: By-Thor's Rolex GMT Master II 16710 Complete Buying Guide
GMTII is really a beautiful and comfortable wath to wear as a daily beater, good choice and good taste.
Regards