Two other quick & easy things to check:
I had installed a new set of points the previous owner had when I bought a tractor. They were Kohler exact points still in the bag. Made sure I cleaned the "oily" film off them. Gap set correctly but got the pops & odd firing at higher RPM. Had to clean them a second time to remove the oxidation that must have developed over however long they'd been on dealer shelf.
On another tractor I had similar issue. Cleaning ground wire bolts, wire connectors, & engine & frame contact points fixed that.