That's not something to worry about. I would just buy a plug wire set. Copper conductor is best. Some folks perfer other types. Whatever you like. I used to say buy good quality, but that is now impossible to determine using brand names as a guide. I now try to buy from local or Amazon, where I can take back with no hassle.
I would put the cause of your trouble at plugs, points or CONDENSER/capacitor. New wires and "tune up" items mentioned is a good boiler plate start however.
If you need help with starting you will have to specifically explain "starting problems". Spark color is subjective. What "starting problems" means is objective.
1. Slow engine cranking speed
2. Starts and dies
3. Starts and runs good but takes a long time to start
4. Takes a long time to start and also runs bad
5. Does not actually start but pops, backfires, spits
6. Starts only when cold or only when hot
7. I notice when it xxxxxx, then it will xxxxxx
8. Please specify year make model of vehicle and motor and 6V or 12V.
9. Yellow spark will explode gas.
