On my Heavy Armor I guy I went to Ebony and then Daedric. I agree that Daedric looks a little over the top, but devs have to make armor non-functional to keep it interesting looking and the Daedric looks sooo menacing.

With 100 Alchemy/Enchanting/Smithing you can wear anything and hit the armor cap.
This absolutely.
My chick wears Legendary Forsworn that's over the cap, but she has the Custom FIt and Matching Set perks.
With my Alchemy at 99 (almost 100

) and all the positive effect perks and 4 pieces of +25% Forty Alchemy gear (I don't bother with the 5 piece glitch) I can make a +120% Fortify Smithing potion.

Then I wear 4 pieces of +25% Fortify Smithing gear and enhance.