Personally, I grind a lot as a OCD habit, which helps in the long run but I understand how tedious that can be.
According to bugsy, the only difficulty is the Scyther right? you can pick up a Geodude from the Tunnel on the way to Azalea, which learns Rock Throw for a 4x multiplier against it, obviously resulting in a OHKO. and from then on, a good geodude sweeps the whole gym, and bugsy's other two panzy Pokemon larvae (Metapod, Kakuna)
I really hope I helped, the geodude learns it at lvl 11 btw :D
and it should be able to take a hit from the scyther, because it resists all his moves :D
Source:Experience, the power of google