Right, I'm fully awake now, and done the maths, so you can ignore the PM if you want lol!
Running five pieces of Tzogvin's gives you 1487 pen, and 14% crit chance (Definitely do this, it really is one of the strongest sets in the game!)
Velothi Ur adds a further 1650 penetration, and a flat 15% damage increase on everything. Both Tzogvin's and Velothi also give 10% crit damage, but it only counts once.
700 penetration from Champion Points passive.
1 piece light armour gives 939 penetration
= 4,776 pen needed
Add a skill with Major Breach - 5948 and you're past the pen cap for overland. So Elemental Susceptibility which lasts 30 seconds and could be on your back bar, or a scribing skill like Wield Soul which you'd use as a spammable every 10 seconds on your front bar, either one will work fine.
Which would mean running 4 pieces of Rage of the Ursauk would be redundant. So, add one piece of light Slimecraw (highest crit chance per one piece in the game - either head or shoulder) and you have the option of any 5 piece set you know. For example, pick an easy overland proc set, that will add extra damage just for attacking:(both of which are easy to farm, or could be bought cheap on Guild Traders)
Defiler from Vvardenfell
2 items: Adds 3-129 Weapon and Spell Damage
3 items: Adds 15-657 Critical Chance
4 items: Adds 15-657 Critical Chance
5 items: When you deal Critical Damage, you summon a Hunger that spews poison to all enemies in front of it, dealing 990 Poison Damage and stunning any enemy hit for 5 seconds. This effect can occur once every 5 seconds and scales off the higher of your Weapon and Spell Damage.
Venomous Smite from Western Skyrim:
2 items: Adds 15-657 Critical Chance
3 items: Adds 15-657 Critical Chance
4 items: Adds 3-129 Weapon and Spell Damage
5 items: Dealing Critical Damage inflicts Hunter's Venom on your enemy for 10 seconds, dealing 714 Poison damage to your target and enemies within 6 meters of them every 2 seconds. This effect can occur once every 15 seconds and scales off the higher of your Weapon and Spell Damage.
or buy the Deadly Strike set from Guild Traders, which will boost both the sweeps/jabs skill, and the amazing, amazing, amazing incredibly powerful execute (that also heals you!) Radiant Glory as both of those are channelled attacks. (It will also come in incredibly handy if you have an Arcanist character as well)
2 items: Adds 3-129 Weapon and Spell Damage
3 items: Adds 15-657 Critical Chance
4 items: Adds 3-129 Weapon and Spell Damage
5 items: Increase the damage your damage over time and channeled attacks do by 15%.
All of those three are medium sets, so you won't pass the pen cap further, and will all add quite a hefty chunk of damage without having to do anything different. If you're using staves as your weapon of choice, I'd pick a lightning staff, as the Ancient Knowledge passive in the Destruction Staff skill line also increases your damage done with direct damage and channeled effects by 12% (again increasing the damage your jabs/sweeps and Radiant Glory do.)
p.s. If you want to see just how amazing the amazing, amazing, amazingly powerful Radiant Glory is, look at the photo below. Despite only starting to use the skill once the enemy your fighting drops to 30% health, it gives by far the most damage of anything. And did I mention it heals you too?