Couple things. 1 the arcs in TW are all locked so you won't gain the benefit of the Tanker AoE stuff. Personally I also don't like being required to take Defensive Sweep. Because of those things i prefer TW on a Brute or Scrapper myself. That said...
Far as the recharge goes, look at slotting the Force Feedback proc wherever you can. Follow Through, Arc of Destruction, and Titan Sweep I think?
I would certainly expect that between primary powers, Tough, and the Tanker proc you should easily be hitting the 70% res to S/L though I admit I haven't looked at Inv in ages. Getting up to 90% is usually the bigger challenge.