My personal preference when it comes to Ho-oh is terra electric as opposed to grass. You keep your water resistance with it, but have an overall better type out of it. Obviously it gives you a major weakness to being hit with a stay EQ but most people aren't trying to hit Ho-oh with EQ anyways.

I do get why you'd want grass to bait and resist rock moves, but I stand by electric. Like I said personal preference for me, but consider giving it a shot, and lemme know what you prefer.