good luck tuning the shifting. reminds me when I brought a bike to a shop one time for a while-you-wait tuneup & new chain. watching a pro go thru the paces with front & rear derailers was inspirational. amazing how quick he was. reassured me it wasn't rocket science & there are a limited number of variables. one just needs immersion & practice. I would love to work in a shop for a while. I know enough to make minor tweaks here & there & some light maintenance, but I appreciate & am willing to pay for professional help