As for the eqipment, you should start off in armor until level 30. At 32, i switched to protector. Wear Protector until 7'th degree is complete, then, for 8'th degree (and later) use garment. You can just stick to protector, it's just as good.
The build uses spear and sword & shield. It requires extensive SP farming ( at least 250 k SP, are required for the perfect dual build).
As for the skills, it’s obvious that the build can be effective only at the lv 80 cap.
The trees are: Bicheon, Heuksal, Fire and Lightning. My personal favourite distribution is: bich 70, heuk 70, fire 80, light 80. You can alter this how it pleases you. Other variations include:
70 bich
80 heuk
70 light
80 fire
OR
80 bich
80 heuk
70 fire
70 lightning.
Now let’s cover the skills:
Bicheon:
Shield technique can save your life, get it.
Knock down books: max all of them, very effective skill.
Stab books: max every book (in PvP, KD + dragon sore + flower bud = at least 7 k dmg)
Passive: no ifs, no buts, max it.
Heuksal:
Soul Spear – Stun effect, very useful, max it.
Ghost Spear – Knockback effect, very good to use immediately after Soul Spear, so the opponent can’t pot.
Consider Chain Spear: books 3 and 5 are pretty good, but they cost loads of SP.
Passive: MAX it.
Fire:
NOTE: take fire imbue, but you can just as well take the light imbue, but fire is better and stronger then light.
Fire shield – immunity to ice – max it.
Flame body – you will use many physical skills: max it.
Fire protection – extra magical defence – max it.
Flame wave series: IMO a must. – leave book 1 at level 1, because maxing it is a waste of SP.
Passive: max.
Lightning:
Piercing force: a MUST for any INT build
Grass walk: max every book of it.
Skip Lion Shout, you are hybrid, not pure.
Concentration: the less damage you receive, the better. Max it
Thunderbolts: max them
Passive: max
Now, let’s cover PvP tactics. PvP-ing can be tricky, but if played right, the char can win very often. At the start you should equip your spear. Fire off your strongest nuke with the spear, and switch to S&S. Then, KD the enemy and stab him. Here, you have multiple options. The one I prefer is to Soul Spear + Ghost Spear. Alternatively you can nuke with a spear and finish the opponent up. If you are low on HP, activate shield technique and KD. (if facing STR builds). If against INT, activate fan Storm. Archers are easy prey. Against them, you should not use nukes, just KD + Stab, (repeat as much as you please), switch to spear and finish off with a nuke, if you get KD-ed switch to shield for better survivability.
As for grinding, you should generally grind with the spear and use nukes. Use a spear when you can one-shot mobs, and a sword where you two-shot mobs. Until lv 30 grind ONLY with a spear. You should grind at the highest level mob, you can one-shot kill. In this case, grind with a spear. If you want to grind two-shot mobs, grind with a sword for better survivability.
Hope the guide helps, and good luck with your dual weapon build!
NOTE: i did my best with the images, hope they are useful.