@Foulcat

Using a higher level egg potion on a low level pixpet won't increase the odds. You only need to a pixpet egg potion that is at or above the target pixpet level. For example you will have the same odds of success at turning a level 3 pixpet into an egg with a grade 10 egg potion as you would with a grade 50 pixpet egg potion. Only thing that matters for success rating is getting the target pixpet to as low HP as possible.

You typically want to get the target down 1 hp for the highest chance. Also the chance of getting an egg is always low, if I remember correctly at 1 hp you only have a 38% chance of succeeding. Also your pixpet glitch level has no effect on getting vivid egg, so you will want to keep your glitch level way down since 100% glitch causes you to lose half your adventure mode pixcoins as well as make your pixpet unable to battle until you use a deglitch potion on it.