gown fittings - a few questions, please help...

I went for my second fitting yesterday, at the first one my gown was definitely a bit too long. I think they over did it, but my MOH said it looks great now and I totally trust her. How long are these dresses supposed to be? My first fitting, I could not walk in it without the front buckling under itself. Would everyone agree that is too long.

My dilemma is that they refuse to steam the gown or the slip until the day I pick it up and they told me I won't be trying it on that day. Now how are you really supposed to determine if it fits if the poofy stuff under the gown and slip (crinolin?) is all crinkled up? I shook the slip a dozen times, but it was still a mess. Will the dress lay differently once it's steamed and the slip is steamed? Is it unreasonable of me to ask to put it on before taking it out of the store as long as I call ahead of time and ask for the seamstress to be present? Can they do anything anyway about it after they shorten the hem to make it longer? Should I invest in a second pair of shoes with a shorter heal just in case I hate it the day of the wedding?

Anyone who is married already have these concerns, but once everything was steamed it all looked good?

I'm very concerned about this...

my dress was all wrinkly too and was not steamed until after my last fitting.. its a lot of work to steam it and they don't want to wrinkle it up again if they have to do more alterations. I actually didn't have the slip steamed because who sees it anyway. Everything was fine after the dress was de-wrinkled. Taking out wrinkles won't make the dress longer.. or shorter.
As for the length, it should not be hitting the floor. You don't want to be tripping all over the hem when you walk around and dance.