You can adjust the throttle with a pare of pliers, maybe even with your thumb and fore finger.
Look for the cable connection at the handle bar grip.
You can probably fix your jumpy throttle right there.
I think this throttle caught most of us by surprise after riding lesser bikes than the Rune... I wouldn't play with adjustment until after you ride her for a few hundred miles.. I think you will find that you will get used to the feel and will not need to adjust it....
I still have under 1000km's on the bike, so will see if it settles down.. probably like any other bike, just have to get used to it... thought it would be more like my 97 Valk but the throttle is closer to the VTX 1800c I sold.. not complaining at all, just getting used to it..