Windstar Signature Expeditions program announced for Alaska

I'm excited to see Windstar announcing details of its signature expedition program in Alaska.

http://blog.windstarcruises.com/2017/11/windstars-new-signature-expeditions-program-debuts-alaska/

We will have an expedition team of 5 on board to do classes and lead excursions.

There are zodiac excursions from the ship in Kenai Fjords, Tracy Arm and Misty Fjords. I think I'd like to book one now and then wait on the others until on the ship so I can use my OBC on them. With about 200 passenger capacity and 6 zodiacs, I don't think the tours will fill up. Not sure which I should book now - Kenai Fjords because it is first and will give me an idea on whether I want to book more or Misty Fjords because it is less likely to have weather/season issues. I'm on the first cruise which starts from Seward on May 17 so Kenai Fjords is the next day and Misty Fjords is toward the end of the 14 day cruise.