A pennant won't always work. The masthead on my Pearson puts the halyard parallel to the forestay no matter how high up the foresail goes. A halyard restrainer that changes the approach angle is the only solution. You might have the same problem, what kind of boat do you have?
My Pearson has an Isomat NG37 mast. It was used on many boats, listed here:
Isomat NG37 Mast