Dress Hem

I'd expect the dress to just touch the floor but not drag. I personally think that your half-inch is going to make quite a difference, but you could always try and see how it looks and if you like it.

If you haven't gotten the alteration appointment for your hem yet take the shoes you are going to wear. A half inch could make a difference if you've already had the alteration appointment for your hem.

So I think dresses look best when they are hemmed to the floor, but you will still occasionally step on a dress hemmed to that height when you are dancing. A floor length hem is fine for walking but I found I stepped on both of my dresses every now and then when dancing in them.

For my ceremony dress, I bought heels that were the right height so that they were not visible when standing and the front of the dress was just barely off the floor. My shoes could be seen when walking, and I could walk fine without tripping or stepping on the dress at all. But when dancing I found I stepped on the dress quite a few times, perhaps because of the weight of the train all bustled, perhaps because of my dance moves.

I bought my dress pre-owned and it had already had alterations and hemming done, so it was really difficult to find the right height of shoes. I ended up in 1.5 inch heels, which were perfect but tried on 1.75 inch wedges that also worked. Many of the 2 inch heels I tried on were too tall, but some were also closer to 2.25 inches or 2.5 inches so that's something to keep in mind. A half inch can make a difference, but how visible that will be really depends on the dress and the shoe.

My reception dress was professionally hemmed and taken in by a seamstress, and she hemmed the dress to be just above the floor in my 2.5 inch heels. After alterations, I realized my dress was sitting lower than I liked, so I took the straps in an extra inch, which then affected the hem height ever so slightly (math would say it should affect the hem height by a half inch or so, but I think there is some additional physics involved that maybe that's not exact), but still wore the same heels and it looked fine. I still found myself stepping on the dress every now and then when dancing, but it was super easy to walk in without issue. The dress was cut on the bias, which may make a slight difference because the diagonal weave/knit of the fabric allows it to stretch a bit more.

With a delicate fabric like tulle, I would be worried about it ripping if it got stepped on. Does your dress have any embellishment on the skirt/train? Because another thing worth considering is that any details that added weight to the tulle would also likely stretch the fabric slightly over time if it is worn all night (because tulle is such a loosely woven material). If your dress has a long train, I think having it slightly short in front will be less of an issue than if your entire dress was oddly chopped off at a weird in-between height.

I'd also consider where you are doing your ceremony and photos. If outdoors, elements like grass and uneven terrain will easily make up the 1/2 inch difference, so it won't matter all that much if your hem is ever so slightly short, because the ground surface will hide your feet anyway.

I know its a lot of thoughts and not much helpful information, but I think if your dress is already in alterations, I would just see how it looks with those heels when it is ready. If you haven't yet purchased the heels, do so that the alterations/fitting is done within the return window so you can return the heels if they don't work. Once the dress is hemmed enough so that it isn't too long that its a tripping hazard, heel height is largely about aesthetics and what you prefer so what looks good to you might be slightly different than what someone else would choose. As long as it looks good and feels good to you, that is what matters!