First of all; dont get 70 Defence, get 78.
I'd recommend the following stats as a start:
5 Attack
5 Strength
78 Defence
If it doesn't work too well, you could get 10, prefebably even 15-20 Strength.
When it comes to gear, you're going to need 30M+.
Buy the following gear:
Helmet: Torags ( Dharoks is just as good, I just like the looks of Torags )
Amulet: Fury, no discussion about this.
Weapon: Darklight / Steel Dagger (p++) / Steel Spear (kp) / Red Topaz Machete.
Platebody: Dharoks ( Again, Torags is just as good, Dharoks is for the looks )
Shield: Dragonfire Shield.
Platelegs: Dharoks ( see Platebody )
Gloves: Regen Bracelet.
Boots: Dragon / Bandos. Dragon boots have the str bonus, but lack a little Defence compared to Bandos ones.
Ring: Onyx ring (i). If you don't have the patience to get this, you could use warrior / berserker ring. I'd use warrior, since it gives you more accuracy.
Cape: Obsidian / Skillcape.
When the battle starts, use Darklights special attack; it lowers you enemies Defence ( Extremely useful against other Defence pure ). Switch to Steel Dagger (p++) or Steel Spear (kp) and poison your enemy.
Then move onto Red Topaz machete, and use it to kill your enemy.
If your going to fight other Defence pures, an Anti-Poison totem would be a HUGE advantage. It makes you immune to poison, but takes a long time to obtain.
Hope I helped
