Confused about dual prot specs

[Kamui988]

Hello everyone, I am a main spec tank looking to actually dual spec 2 different types of prot. One of my most respected tanks is actually dual spec'd double tank, but I do not understand the utility between the 2. I came here wondering this and wanted to ask you fine people this. Here are his 2 spec's along with his glyphs:

Talent Calculator - World of Warcraft (http://www.wowhead.com/?talent#LVZGV00xZVotrg0zidIzsGo:dciMm0)
Talent Calculator - World of Warcraft (http://www.wowhead.com/?talent#LAM00fZhbZVhtrx0zidIzsGo:dcAMm0)

Thanks, Kam

[Synapse]

The tclap's an oddity there but it's basically a threat spec and a survivability spec.

[Kamui988]

Thanks for the reply, also this has bugged me for a while for warriors and I cant find a clear answer. What are the caps/soft caps on stats such as hit/expertise/dodge/etc.?

[Synapse]

They should be on the library here. 8% is the hit cap for most stuff, while 26 expertise cuts down all dodges. Avoidance doesn't "cap" per se, but it loses unitary value as you stack more and more, but there's little to do about it.