The 5.0 lever was factory installed in several transmissions and they didn't suffer from severe overlap.

The 5.0 lever, itself, isn't the bad guy, the combination of that lever and the rest of the trans setup is. It would be easier to pull the valve body and place a restrictor orifice in the front clutch circuit than to try to change the lever in situ. It there's already a restrictor in place go smaller.

Simply loosening the kickdown band adjustment is the easiest option.