I've historically had very little luck getting the standard Triumph clutch to work properly without dragging, but finally got there...
I replaced all the components on my T140 clutch a few years ago, as along with the notching on the outside of the hub, the inside gets badly worn where the shock absorber spider rubs against the face plates.
I must say I've never seen the wear pattern like yours before; mine have always been notched on the spline grooves only.
The springs themselves shouldn't be an issue, unless they're not strong enough.
The standard pressed steel pressure plate is also barely fit for purpose - I went through the local spares dealer's entire stock to try and find one which was actually flat and failed.
It's easy to see if this is warped when setting the spring tension. Mine was all over the place
The solution was an SRM alloy pressure plate, which is infinitely superior, and got my clutch working properly, although it was a bit heavy to prevent slip.
I finally fitted a Burton Bike Bits belt drive to mine, and it came with a set of alloy friction plates which put an additional one in the stack - once I fitted this I had a great clutch; a lot lighter and no slip.
But it still sticks if it's been stood for a few months, so back to the traditional kicking over with the clutch pulled in to free the bl***dy thing off before every ride