I too have a baby stay on my Pearson 10M and have note flown a spinnaker yet on my boat. I am getting there...
BTW, what is the purpose of the baby stay other than allowing us to induce mast bend using the backstay adjuster? Also, The baby stay can easily be detailed from the deck, however how does one stow it out of the way? We cannot bring it to the mast as the length is longer and it is not straightforward to bring it aft and attach it somewhere as we do the spare halyards.
Appreciate your thoughts. Cheers.