About the linkage stoppers, yup sometimes you need to drill out the servo arm holes larger OR, if said servo is hard to get to later i attach my linkage stopper to the control horns, I'd say 90% of my planes i put the linkage stoppers on the control horn. And seeing as i have ape hands, I usually don't have a small drill bit that isn't broken so I heat up an appropiate sized finish nail with a propane torch and melt my way thru, works on woos control horns to, just make sure you hold the nail with pliers unless your fingers are made from asbestos.