Well, it depends on which amazing morph combo you're interested in! Which ones in particular would you like to make?
With just pins and pastels you can make lemon blasts and killer (super pastel) blasts.
If you throw in a lesser, you can make king pins. If you throw in a mojave, you can make jigsaws. if you add pastel to either of those, I forget what you call them, but they're GREAT.
You can also add spider to the pinstripes to get spinners. Spider to lemon blast has a 1:8 chance of making a spinner blast (pastel spider pinstripe).
Most of the time the two-gene breedings are 1-in-4 chance per egg. Three gene breedings are generally 1-in-8 chance per egg. Adding a super pastel instead of a regular pastel increases your chances of getting the awesome combo by a factor of 2.
(I also like Albino pinstripes. But then you have to work a recessive trait. So the first thing you'll produce are pinstripes het for albino, which will just look like pinstripes. THEN you have to breed THAT back to an albino to get the 1:4 chance of an albino pinstripe.)