"Introductery Armors for G Rank"?
I actually used Dark Akantor armor all the way until my Urgent to hit Hr9. It was lacking on defense at that point in the game (as you mentioned), but I liked the skill set too much to bother with anything else.
You might give Hermitaur Z a try. While the Guard+1 won't serve you any purpose with Longsword or Dual Sword, it does have the Guts skill (prevents you from getting 1hKO'd if you're over 2/3 HP). Usefull if you arent familar with dodging the G rank monsters attacks (some of the G rank monsters in Rage mode are quite capable of 2hKO'ing you, even with 600+ defense).
Ceanataur Z is also good since it can be gemmed for Sharp+1, SharpKnife & Speed Sharpen (great for DS). You will however, have to deal with Defense Down (even if you use all slots with Defense boosting decorations, you can't remove it completely).
There's also Kut-Ku X (if you're looking for G Rank worthy defense early on). Can give Attack Up, Recovery Speed Up, & Psychic Vision. Don't forget to gem out the Defense Down, though.