I installed the CJ Designs footpeg extenders.  It takes a bit of time to get it done.  My procedure may be different than yours.  Removing the stock pegs is simple.  When I tried to mark the exact spot to drill I found that the marks were not visible.  So I spray painted a bit in the areas for the front/rear holes.  When dry I marked them without issue laying them flat down so the cleats of peg were level with cleats of extenders.  Drilling was a multi step process.  A pilot then final hole for the holes.  A bit of back and forth to make sure all was lined up carefully.  For the reinstall on the bike you will find that the spring is stout enough to balance a garage door.  I required a long nose vice grip pliers to squeeze the ends of the spring to partially insert into position then with a screw driver from the bottom into the spring and the pin positioned at the top the spring could be let go.  It still takes a bit of messing with but it was the only way I could do it.  I will try the pegs today.