Posting as player, not as DM and only trying to be helpful, not criticize, but I know my as person persuasion skill is very low, so please bear with me if it doesn't sound helpful at all. I only try to be
[ +- ] My assumption
Probably I'm wrong, but I feel party decisions are never made, or made much too late, due to anxiety that a potentially larger problem may arise. Which could probably indicate decision paralysis or an
analysis paralysis
Do you fear of making mistakes ? Fear of regret?
This may have been a geniality of module designer or coincidence, but I believe that the idea is following: all the hints that designer of this dungeon put there are not designed to help you, but to fear. To fear the mistake.
So trying to be helpful I'm reading some articles on overcoming this paralysis. Option to base decision on data is not your option - this module is designed to force you go train and error path. But other ides such as "accept that mistakes will happen", "use deadlines" and "Don’t consider too many options".
Your DM could try to help implementing last two if you ask him, but yet again - I'm posting this only as a person trying to be helpful. As a DM I will be waiting for your decision as long as it takes (well probably not longer than 2 weeks).