Radio silence, but I did look into this and I've decided to look at getting:
SONOLASTIC NP-1 Polyeurethane Sealant Caulking White
This is available at a local brick/mason place near me. And in looking at this, it seems that just about any sealant should work, as long as it is polyurethane.
I am also going to throw caution to the wind and try and use my Makita Multi tool with a snapper blade and VERY carefullyand slowly try and remove some of the old caulk. If it feels like it's not right, I'll stop and back to manual labor.
Sometimes I wish I were living in the stone age. Then I would know I'm the smartest person in the world.