Stealth Training Guide (what to wear)
00-25 Train from Theif Guildmaster NPC
25-64 Leather Gorget, Gloves
65-84 Ringmail Gloves, Ringmail Sleeves, Leather Gorget
85-95 Ringmail Legs, Leather Tunic, Studded Sleeves, Studded Gorget
95-120 Leather Legs, Leather Cap, Chain Tunic, Ringmail Sleeves, Studded Gorget
Only took me a couple of hours once I followed the above armor guide from Super Bob