What does Arcane Smithing have to do with unenchanting the pre-enchanted guild armors??

Nothing.

Also, I enjoyed the more combat-related enchantments on Nightingale. If anything I found it better than the "stealth" enchantments on the set, as I didn't need to stealth bonuses at that point and the combat performance boost was nifty.

It doesn't always seem to work the way you want it though. I've been tryimng for days to duplicate the Tavern Clothes (they're hard to come accross without pickpocketing them). I equip only the clothes but it keeps duplicating gold diamond necklaces instead. It seems to be random. For a while I kept getting duplicate Ancient Nord Gaunlets. Even though I had the entire set of armor equipped. Why only the gaunlets. At one point I was getting deadric shields even though I was equipping ebony shields.

I can't figure out how to duplicate what I want.

I actually use only the boots and the guantlets ...thats it...archmage ropes with maroki mask...im a mage but use sneak and bows a lot ......i have to admit that the whole set looks bad a** ......

I mix & match the TG and DB armors depending on what I expect to face. Currently wearing TG armor & hood, Nightingale boots and gauntlets. After improvment at the blacksmith's, very good for dungeon crawling. I'll switch out to the DB gauntlets for assassinations.

If I remember correctly, this only works for items that the player has enchanted. SOL

At least I don't have to drink my own sweat and urine like the Fremen suit ;>)

MIx-n-match would be fine if Beth hadn't put in a perk to boost the armour rating for a similar set. It's fine for ranged and stealth as enemies never close enough to see you, never mind hit you, but for 1H/dual-wield and stealth then I miss that bonus until stealth is VERY high - usually boosted over 100. As i said earlier, the Nightingale armour is OK, but it's far better than the other stealth armours available. I mean: poison resistance for DB armour. Why? There's only about two things which use poison attacks.

And those two things that use poison attacks are Falmer and chourus. A pack of Falmer are real nasty. I prefer to sneak by them and maybe just pick off one or two that may be in the way, but if you're doing the Blindsighted quest at level 46 Karliah and Brynjolf are just absolutely stupid and as regardless of where you park them, go charging in as soon as you fire the first arrow, alerting everyone of the Falmer.

The upside is that if you remain hidden, they draw all of the attention and you can just sneak past the mob. They're essential and won't die, and will reappear when you meet Mercer. I tried to stand up fight with them and got my butt handed to me. Poison.

Actually, the exploit only removes enchantments that you put on generic armor yourself, and it doesn't duplicate shields, only head, torso, hands and feet. If you duplicate armor that you obtained with enchantments already on them, they will duplicate exactly.

i tried it last night, but not on nightingale.
tried it with ebony mail, and yeh it didn't remove the standard enchantments so i dont think it would work on nightingale..

BUT it did duplicate a shield with powers too.. cant remember what its called but it was the dwaven one from a daedric quest.
also duplicated gold necklace and ring.