Personally I would use 3's and 4's and save the 5's or higher for your T2 set when you finally acquire the set pieces you want. Why waste a 5 on a pvp or T1 purple when you will upgrade it within a week?
But if you don't mind spending diamonds to unbind the 5's then go for it.
5's aren't worth unbinding. The most expensive 5's cost something like 25k, and they're 50k to unbind.
You should use the enchantments you feel like you can afford. I use rank 6 defensive and rank 7 offensive in my T2 gear, since those are around ~150k each. Rank 4's are barely worth anything (< 1k)and you should at least be using them.
Comments
But if you don't mind spending diamonds to unbind the 5's then go for it.
<Rarely Sober> - Beholder
You should use the enchantments you feel like you can afford. I use rank 6 defensive and rank 7 offensive in my T2 gear, since those are around ~150k each. Rank 4's are barely worth anything (< 1k)and you should at least be using them.