Is my dragonites move set good?

good for attacking/prestiging but its dragonites worst possible moveset to put in gyms

not really. Every dragon charge move would be better for attacking. And on defense the same. After Steelwing with Hb the second worst moveset you could get

Like yourself, I have only one Dragonite, and DB/HB is its moveset.

And she's a BEAST!!!!

And yes, I'm aware that this is not her optimal moveset,
and I'm sure that a DB/DC 'Nite would wow me with its balance of power and flexibility,
but I have never tried my DB/HB Dragonite against anything and been disappointed with the results.
She always impresses.