I've been reading up on the WoW Warrior Forums about gemming for Armor Penetration as an arms warrior, and I just have a few questions about what this exactly means. People talk about not gemming for ArP unless you have a ArP proc trinket (like GT,MR, or NES). I was lucky enough to win a roll on the NES trinket my first run, and I decided to beef up my Arms gear.

When talking about gearing yourself for the soft-cap for ArP, i'm assuming that means by gear alone? Or does that mean gems too? I'm not sure what the exact percentage gain from NES is but, it gave me tons of ArP (around 73% with the buff) and was wondering if it is worth gemming for ArP until i reach that soft-cap and then gemming for Strength after that.

Here is my armory link:
The World of Warcraft Armory
(i know i didn't modify my bracers or enchant them, and i have a few items to replace here and there)

I guess to sum up what I'm asking, after finding out what exact percentage NES gives, should I gear for the ARP soft cap through gems, gear, or both?

Thanks in advance!