Speaking of Dragon Tail, meron akong dalawang concepts para dun.

Moves lang yung ilalagay ko tsaka yung explanation since halos standard EV spread naman ang gagamitin ng dalawa na to.
Arbok (Intimidate/Black Sludge)
-Glare
-Dragon Tail
-Coil
-Gunk Shot
Phazer set + 100% Glare, requires 1 turn of set-up kung gusto mong gamitin na 100% ang Dragon Tail at Glare.
Priority doesn't really matter kung phazing ang focus.
Synergies with Entry Hazards (Spikes/Stealth Rock). Sa turn na nilabas mo si Arbok, due to Intimidate, medyo mas mataas ang set-up chance. Go for 1 turn Coil. Next turn, either Glare your opponent (if possible) OR Phaze it using Dragon Tail.
Though mas preferable ang Roar set kesa dito. Okay din mag-experiment since pareho naman silang -priority.

Iwas Soundproof tapos x2 sa Dragon type, x1 to all other types except Steel. LOL
Serperior (Lefties)
-Leech Seed
-Coil
-Dragon Tail
-Giga Drain/Glare/Protect
75/95/95/113 = Good stalling (nice sana pero panget ng defensive typing kasi Grass) + Nice speedy Leech Seed.
Coil set din para sa +damage sa Dragon Tail at accuracy. +Defense din.
Last slot, either Giga Drain for quick recovery (depende sa HP/type/spdef ng kalaban), Glare for PAR support o kaya Protect para sa Stalling.