Is it best to wear a mixed set of armors when trying to level up the skills? I am wanting to go 2H w/ Heavy Armor, but I like the extra carry space available from light armor when doing dungeons. Will my Heavy Armor skill raise if I wear a Light Armor Chest, Gloves, Boots and a Heavy Armor Helm? And if so, is there a difference (on how fast it raises) if I have a full set of Heavy versus a partial set?

Thanks.

You want to go 2H w/ Heavy Armor, but you want to wear Light Armor for dungeons? When were you planning to use the Heavy Armor?

Just go 2H w/ Heavy Armour, and don't worry about weight; loot the best stuff and leave the junk. Should not be a problem.

Besides, get it levelled high enough, and there is a perk to remove said weight.

Once I got the perk to make it weightless.

If you constantly wear light armor, your Heavy Armor skill is not going to raise fast enough for you to ever really benefit from the weightless perk. Just go with the heavy armor.

Not very sure yet about how works in Skyrim, but in the past when the enemy hit you, that blow can be randomly in any of one of your armor parts, this means that if you have for exemple a heavy helmet, and all the other parts light armor, you will take forever to rise the heavy one, because it will rise bits just when you take a blow in the head. Beter is to use a complete set of the same type and model (because there are perks for the use of a complete model of armor).
But i know this from Morrowind III, don't know yet if in Skyrim all the diferent parts in use lvl with any hit, or if it just lvl when a certain part is hit.