If the budget doesn't quite extend to a full set of PDQ tt bars, how about just upgrading your alloy extensions to carbon ones instead? These will fit any 'standard' tri-bar set-up that uses 22 or 22.2mm extensions. They're 330 mm in length with a 25 degree upturn to prevent numb fingers and sore wrists.  Only 116 gms per pair.  Pre-drilled for gear cables (would have been 120 gms + without the holes!).  Upgrade your soppy alloy heavyweights to these stealthy go-fast light-as-a-feather little beauties. Available in gloss or matt.