TBH, I prefer the Cobalt Haubergeon over the tortoiseshell.

+6 STR, +6 Attack Power, +6 Accuracy.

Get the accuracy that would from the dex on the tortoiseshell mail (give or take a few), plus six strength at the cost of two attack power. Cobalt Mitt Gauntlets are also a better choice than cobalt vambraces, IMO. just depends on if you want STR or DEX, though. Mitt Gauntlets are +3 STR and +3 VIT

Cobalt Sollerets (Red) also have +3 Accuracy and +3 STR.

http://i.imgur.com/GjMng.png

Best materia for body would probably be Savage Might - which is crit attack power.