Recommended ArP for a full pve bg hero

I want to know what is the recommended arpen value for full pve bg heroing.

I read that arpen reaches a point where it doesn't help against platties because the damage increase from physical shots is lower than the damage increase that you would get from magical shots if you had taken agility instead.

I also want to know what you think about spellpen. Many players don't take any at all, but I feel like not having any severely diminishes the amount of damage that I do, especially at the beginning of fights when everybody has mark of the wild.

Thanks!

1400 Arp is Hard Cap.
You need 75 SpellPen for "PvP" for penetrate through Mark of Wild etc.