Adjusting torque converter lock up

Gents,

My torque converter locks up (4HP22zf) at almost 100km/h, I'd like to have this happening a bit sooner.

I was told by Ashcroft transmissions that a spring in the valve body needs to be shortend, I took 3 windings off from the spring, but it still locks up at the same speed, if I make the spring shorter it will be loose in the bore..

Anyone here who done this?

Thanks