I would like suggestions on movesets and Ev's for the Flygon I am planning to raise from this Trapinch

Trapinch Lv20, Mild Nature.

HP: 50
AT: 50
DF: 23
SA: 27
SD: 24
SP: 15
Current Ev's: Three for Special Attack, One for Speed, and Zero for all other stats.

Any suggestions will be greatly appreciated.
Thanks in advance.