Strength vs arp on 70 twink

Hello
Long time wow player but 1st time twinker.

Started off with 2 lvl 70 twinks, dudu and war as I enjoy the outlands content. Question I have is for their dps specs gemming.

With warr I've got arnd 75% armor pen atm (19 gems are armor pen) and was wondering if it would be worth changing them all for strength.
19 gems * 20 str =380 with improved berserker talent (+20% str) it would be 456 str. so 912 attack power.
Dunno however what that compares to when losing 75% armor pen. Anyone know how to sim and can explain. Ty