3peaksgold, welcome the to the board. I have read a few posts about those that have tried and failed to successfully adjust the shifter lever. However, I don't recall seeing where anyone has successfully adjusted it.
I have small feet and it is sometimes hard to shift with my tennis shoes on so I went to ace hardware, got a small length of clear water hose, can't remember the type, cut it to length and slipped it over the black rubber piece on the shifter. took it out for a try, came back and siliconed it and was done.