My shifter is on the Top tube, a bit behind the stem. So I can use either hand, in turn or out turn. ha
The cables straddle the TT nicely. So they are not out front squirming with every turn. Bound to last far longer, 10,700 miles now with no adjustment. I made the post myself with a 7/8" piece of handlebar and a sawed 3" piece of old bike tubing. Angle it down some, weld and then hose clamp it. I wrapped a shoelace around the shifter to try give it some grip.
A few years ago at a LBS I saw a grip shifter with a 2 finger lever. I said to them it was so stupid. Even alone I wouldn't want a 2 finger. Where the hell do I rest the other fingers?