I use it with Flame Thrower just because I can't deal with 2 moves that can miss in the same Pokémon. Just a personal stuff. But I know that Fire Blast it's just better. I wait for the video about DD Focus Tar because I think that My evs are Bad for that set.
This set is primarily used with Celebi so swampert really isn’t an issue. And is easy to chip wear down with spikes/tox. Keep in mind this set is niche it’s not for every team structure. Reg mix Mence is a lot more splash-able.