About all that can be done is an improved coil, other than using quality replacement parts. If you have good hands and eyes, you can tell if the centrifugal advance needs to be rebuilt. It probably does, and this will do as much as anything to improving the function. I find that the pins and the slots they run in on the weights to advance plate linkage wear around the cruise at 3krpms area due to vibration and lack of lubrication, the the timing starts jumping around there, losing you optimum advance at that most used area. When I did mine, I also had a bad or weak coil (can't 'member, it's been decades ago, now), and I bought an Accel Super Coil, and had no problems with it. I bought it because I needed to use up a credit at the speed shop where I got it. Any quality coil is adequate.

In truth, if the stock setup does an adequate job of firing the mixture, nothing you do to it will make any improvements. If the spark is hot enought to give an acceptable probability of combustion, and happens at the right time, nothing will do more. Addtessing the timing wear will make it happen at the right time.

Test the vac advance can. You don't need a special tool, just suck on the hose and see if the actuator moves, and moves the timing plate without slop. Often, the diaphragm in the flying saucer is cracked. There are centrif advance vs. rpm and vac advance vs inches of mercury in the fsm, and you can test both with no more than a timing light and vac hand pump or other source (sucky mouth may be enough, with a gauge in addition. Disconnect and plug the vac hose when you check the centrif advance amount (need a helper watching the tach for this), and hold a high idle and hook the vac pump/gauge and apply vac to the spec and check advance with the light. A timing light will reveal spark scatter if you hold a 3000 idle and watch the light. If the advance is worn, the spark will jump around in advance amount.