Enchanting armor and weapon

Hello, im planning to make ench. Bedron set and some weapon. I was reading about success rates from +1 to +12 in other thread and so on, but i am wondering about two things:
1. What option stone should i use for set? in Exchange market i saw many sets with added HP for example 300, but no added critical rate, no damage drop (what in my opinion is much better than added hp, maybe im wrong). So after seeing whats in market i decided to make it my self. And in what steps i should use preservation stones? And if forging or enchant upgrade wont succed, which of my items will remain? Armor parts or armor parts + option stones?
2. And second question about those weapons. I have read that weapons are not as often upgraded after enchanting as armors, so after i make Enchanted weapon, i can stop to upgrading it?

Thanks for your detailed answers, mates!