Always enjoy Kmeeg's input!
I put 8% HoK in my GS as well. It is not like the reaver need it, but I do use the 2h sword on other classes, which most certainly need some HoK. I prefer having the ring slot open for flexibility. With 8% on weapon I do not need a 10% HoK ring on some classes (10% HoK ring vs 20% Critical Damage Ring vs Ability Ring)
I don't like Armour Penetration on the Hakkon GS since it is not really that great for the Avvar. Also Armor penetration is not that good on high base damage weapons compared to low damage ones due to how the damage formula works. (not dps -> base damage!)
Ornate Pommel vs Etched Pommel:
Reaver(1 Dragon Rage & 1 Crit Damage)
Ornate Pommel(+Attack) - 20% Critical Damage + 4% Attack + 8% HOK
Ornate Pommel(+AP) - 20% Critical Damage + 6% AP + 8% HOK
Etched Pommel(+Attack)- 29% Critical Damage + 11% Attack + 0% HOK
Etched Pommel(+AP) - 29% Critical Damage + 18% AP + 0% HOK
Result:
Ornate(+8% HOK) vs Etched(+9% Critical Damage, +7% Attack)
Ornate(+8% HOK) vs Etched(+9% Critical Damage, +12% AP)
Katari and Avvar - Multiple Options
High-Promotion Options:
Ornate Pommel w/ 2xCD
Ornate Pommel(+Attack) - 40% Critical Damage + 4% Attack + 8% HOK
Ornate Pommel(+AP) - 40% Critical Damage + 6% AP + 8% HOK
or Etched Pommel w/ 1xCD + 1xHOK
Etched Pommel(+Attack)- 29% Critical Damage + 11% Attack + 10% HOK
Etched Pommel(+AP) - 29% Critical Damage + 18% AP + 10% HOK
Low-Promotion Options:
Ornate Pommel w 1 x CD + 1 x HOK
Ornate Pommel(+Attack) - 20% Critical Damage + 4% Attack + 18% HOK
Ornate Pommel(+AP) - 20% Critical Damage + 6% AP + 18% HOK
or Etched Pommel w/ 2xHOK
Etched Pommel(+Attack)- 9% Critical Damage + 11% Attack + 20% HOK
Etched Pommel(+AP) - 9% Critical Damage + 18% AP + 20% HOK
Result:
Ornate(+11% Critical Damage) vs Etched (+7% Attack, +2% HOK)
Ornate(+11% Critical Damage) vs Etched (+12% AP, +2% HOK)
It's splitting hairs. Neither is "absurdly" better. Etched is better for the Reaver. Ornate might be better for the Avvar and Katari.
Obviously, if you don't have a Superb HOK rings, you should use the Ornate. 
I currently use the "Firm Greatsword Grip" w/ 18% Critical Damage and 9% Armor Pen. But, I don't really play the Reaver too much these days. I should get rid of the Armor Pen.
Which grip do you use Kmeeg?