Customizing your weapons, shields, energy items, armor, runes, and upgrades?

Forgive Me for my NooB question.

However through my research I am still having some trouble figuring all of this out.

Here is what I have learned so far

Weapons - Can have as many as 2 upgrades
Shields - are not customizable
Energy Items - are not customizable
Armor - Can be purchased in pieces and runed
Upgrades - for weapons

Background -

I have a W/Mo that just reached 20th level
I have not really given thought to runes or upgrades to my items, I just use what I have acquied so far
I feel now is the time to learn more about customizing so I can get a better feel for the game.
I've read a couple of guides on here, however I found most of them are outdated now.
I'd like to know what the possibilities are for customization

Since I'm a W/Mo lets talk about what I use the most (attributes)
I use Strength, Swordsmanship, Tactics, Healing, and Smiting for the most part.
Lets say I had a Duelist Helm with +1 Swordsmanship
I know I can put a minor rune of swordsmanship on to add a +1 bonus
If I add a superior rune to a +1 duelist helm, will it become +4 Swordsmanship with -75 health? I cannot seem to find a superior rune of swordsmanship, so the same question could be applied to the gladiator helm with +1 tactics

Lets say I have all Ascalon armor, would using 1 superior rune of absorption add to the damage reducer? or is that already maxed out?

I've noticed that 1.5k Gladiator armor has a +8 Energy for the entire combo, and that there is a sword that provides +5 energy. Are there shields with + to energy as well?

I would imagine 20 +8 +5 +10(or more / energy item) would work quite well for any of the W/Mo or W/E out there

What upgrades are best for a sword and why?
Can I find shields out there with more than 2 benefits?

If this has all been covered, links to the latest guides would be appreciated since I've been finding the out of date ones.

1) Yes, you would have +4 to Swordsmanship and -75 health
2) From what Ive read and hear, You really only need 1 piece of "Reduce Damage" armour. So you should only have 1 piece of ascalon or Knights Armour since the "Reduce Damage" is universal. You CAN add a Superior Absorption and it WILL reduce damage. So 1 piece of knights/ascalon armour and Sup. Absor. will STACK
3) From my own experience Ive never seen a shield with energy
4) Most people use +30 health and 10/10 Sundering ( armour pentration) upgrades. Some people like Furious hilts but I prefer them on Axes since they use more adren.
5) I've never seen a shield with more than two mods on it.

Thank you for the quick reply

another question

if each piece of gladiator armor has a energy bonus, why wouldn't each piece of ascalon armor reduce damage?

Well, Energy is WAY different than "Reduce Damage". Just test and stuff have been done, and they concluded that only 1 piece of ascalon/knights armour is need. Just the way Anet made things.