Jett Skill Build.

I would probably leave Solar Array at 21 in favor of maxing Gamma Missile at 120. I feel like Gamma Missile is going to give you more utility in 4th job than Solar Array since Solar Array is mostly outclassed by Suborbital Bombardier whereas you never get a better mobbing skill than Gamma Missile.

But Solar Array range is quite good to begin with and an excellent 3rd job skill. And it's not like you can't max Gamma Missile later in 4th job due to the lack of more Skills to put SP on.