I still don’t have a Clockwork Gnome so I used Mechanical Pandaren Dragonling (1, 1, 1). Bombing run, then Breath until MPD resurrected, Explode. Finished Ruinhoof off with my last pet, Lil’Bling, but he’ll be just about dead so most any mechanical pet would do.
OMGOSH this totally worked. Please submit it as a viable Strategy! Confirmed Mech Pandaren Dragonling 1,1,1 bomb run, breath breath explode or a new bomb run on resurrect. then lil bling 2,2,1 go make it rain, then inflation and boom dead. hold 3rd powerful mech in play like menagerie custodian with ion cannon or something