Bar ends for Cannondale Bad Boy Solo

[highway]

I have a Bad Boy 3 speed, with a lefty fork. It has the "grifter" style 3 speed twist grip gear change. I'd lke to fit bar ends but I'm told these don't fit because of the gearshift being what it is. Is there a PH way around it?

[highway]

While I'm waiting for the definitive answer, 3 rd gear is slipping a bit. The is a little adjuster near the gear Selector. 1st and 2nd are fine but in third there is a clicking sound which is irritating. Is this a sign of issues to come? The 3 speed hybrid appealed as result of lower maintenance...

[itsnotarace]

Ergon do a range of integrated grips and bar ends compatible with gripshift