I found this thread which was very useful.

We went with a Dymeema halyard for the Spinnaker. This has a tendency to stretch a little which is OK for a Spinnaker (not a main or Genoa). We are sticking with Vectran V-100 for the main and Genoa halyards.

As I understand Vectran is the USA brand for spectra while Dyneema is the EU brand.

Reference:
V-100 https://www.neropes.com/products/performance/product/detail/v-100/
Dyneema https://www.neropes.com/products/performance/product/detail/endura-braid/