Excursion start time on tender port in GC

[KB Cruisin]

We are going to GC on Liberty of the Seas.  We get in at 10 am.  I wrote an excursion company that told me that the best tour time would be 1115 am.  When I tried to reserve it, someone else from the same company wrote me back and said the check in for the 1115 is at 1045 am so that I would not make it since GC is a tender port.  He suggested the 1:45 pm.  However, this tour is almost 3 hours and I am afraid we would miss the ship (leaves at 5 pm), especially since this is a non-RC group.  What do those who have been there think?  With the ship coming in at 10 am at the GC tender port, could we be in GC by 1030 am (allowing 15 minutes to get to excursion to check in)?  We do have the key so we should be near the front of the line.  LOS only has a single GC excursion so I am trying to make a non-cruise excursion work but sure don't want to miss the ship.  

Edited April 1, 2022 by KB Cruisin