To answer my own question:
Actually, you should use physical protection equipment.
The main death attack that grim reapers have is the death beam, but it only hits the line in front of him. Considering that you will never be in front of the grim reaper, you almost never get hit by the death beam.
The explosion wave is the attack that the grim reaper will almost always hit you, plus the melee attack of grim reapers that can hit 600+ on a paladin using bow/crossbow.
It's best to use foxtail amulet than Koshei's, and prismatic legs than yalahari.
The best helmet is elite draken helmet, and the best armor is depth lorica.
When it comes to boots, you should use soft boots to spare some strong mana potions.
Also, use mana leech 1 on helmet and weapon and you will almost never use strong mana potions.
I can get 1kk/h on green stamina, no xp boost, no prey.
Now that the respawn is doubled, a RP lvl 100-150 will need only one cave on yalahar to hunt.