tv adjustment on sunbird

[asustek]

I was wondering if you guys can help me to get the best adjustment of the throttle valve cable for th125c on 93 sunbird with 3.1. when i got the car it shifted at full throttle above the rev limiter which caused me to lose performance, but after i adjusted it i went too loose and it shifts immediately(too soon). I am planning to adjust it again but was wondering what the ideal shift point would be considering the engines low powerband.

Thanks