I looked around some but decided to ask instead, so here's a couple of questions
Currently I'm using legendary ancient db armor, using a bow 99% of the time, and I'm going to switch to forsworn instead with some nice archer enchantments.
But all items are not going with all enchantments, whats the rules there?
Enchantments work on 4 pieces of apparel. You can find it out yourself at the enchantment table. Select the enchantment you want, and see which items are not grayed out. For archery it's head (hat or helmet or circlet or hood) neck (necklace) finger (ring) hands (gloves or gauntlets). For sneak it's neck, finger, hands, feet.
Currently I have broken down some fortify archery item, but it seems weak. Is the strength of the enchantment dependable on the soul gem only or do i need to break down a really good item to get the skill? in that case, what would be the strongest for archery?
Strength of enchantment depends on your enchanting skill level, the perks you take, and the size of soul gem. To learn fortify archery enchantment, you need to disenchant any item you find with that enchantment. It does not matter what you disenchant.
Is there a difference in strength on the enchantments on different armors?
No. They are all the same.
What perks in the enchantment three should i pick if I only want to enchant fortify archery/sneak on armors, and not on weapons?
Enchanter on the bottom of the tree (5/5) gives you 100% boost on the enchantment strength.
Insightful Enchanter above that gives you another 25% boost for fortify archery and fortify sneak.
With Extra Effect at the top of the tree, you can enchant your ring, necklace and gauntlets with both fortify sneak and fortify archery at the same time.