Everyone is telling you to make a pure. I would like to suggest something out of the box:
F2p Mage Tank: 40 defense 59+ mage.
Go for 50 runecrafting to help you train mage up and access Great orb project. Mine/wc for cash to train mage up, fist of guthix is also free mage xp at half the xp values.
Pking Gear:
Runecrafter Hat (Great orb project)
Any cape
Amulet of Power
Any staff
Rune kitesheild
Combat top (Fist of Guthix)
Runecrafter Gloves (Great orb project)
Combat bottom (Fist of guthix)
Fancy boots (Stronghold of security)
Explorer ring (Acheivement diary)
---------------------
Magic Bonus: +24
Defense Bonus:
Stab +58
Slash +65
Crush +62
Magic +33
Range +56
(not bad at all if u ask me far better then a rangers bonuses)
Using Fire blast as your attack you would be facing full rune (-24 mage defense) and full range (+24 mage defense, assuming pure)
Your +24 magic bonus is on an equal level. You can always switch to rune chain when needed sacrificing -22 magic bonus but only while eating/tanking.
At 80+ mage you can afford more defense levels. And 43 prayer would cost you 5 combat levels (which isnt much)
Iv'e seen this set up used effectively during BH 1vs1 craters. I'm sure it would be feasable if somebody had put the time into obtaining the stats/items needed. I hope this helps either you or anybody reading this thread.
Cheers.
-Persia_ugly