As Szabo and detlef have said, the Atheling Mantle is very easy to obtain, and is easily better than both the back pieces you're debating. While there are a couple other pieces that are situationally better for TP, Atheling Mantle is pretty much the optimum TP back piece for most every job that can equip it.
My thoughts and reviews
Lady Jinte wrote:
Vlorsutes' Negotiation Skill rises 0.2 points
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on all sorts of sci-fi stuff...and things.