Your build looks pretty good
Eventually you will want to add the buffs from the lightning tree, and fire shield so that you are ice immune at higher levels. But overall everything looks good.
Piercing force should be the first 1. That way you will hit a bit higher damage.
There is no reason not to go garment all the way.
Garment speed boost,high magic defense, low physical defense.
Armor high physical defense, low magic, and slow as hell.
Protector in between armor and garment.
For every str point you add you gain phys defense+hp+physical attack power.
For every int point you add you gain magic defense+mp+magic attack power.
So garments are recommended because you have high physical defense already. By wearing garments you have a more balanced defense.
If you feel that monsters are doing to much damage to you then go protector if you like, but armor truly isn't necessary. (Most monsters do physical attacks)
I would not recommend carrying a 9gap that is not farming. That is gapping with the largest gap possible. The purpose of farming is to bring 3 things together.
1. strong weapon
2. monster with high spawn rate
3. 9 gap(max sp, least xp)
That is why when people farm at lvl 16 they delevel back to 16 to farm some more. If they out level the monster they loose sp per kill.
I would recommend carrying a 4 gap. If you find that you are running out of sp open the gap up. If you are collecting sp, then you can drop to a 3 gap.
Leveling with a 9 gap is torture.
