Gay wedding traditions are as similar as you want them to be. Some practices are gender-specific. Therefore, traditions such as one of the couple walking down the aisle to meet the other at the altar may not be appropriate. Of course, if you wanted to do this, that's fine. Otherwise, the couple may walk down the aisle together or sometimes two aisles may be organised. I think it's important to organise the day as you want it and not worry too much about what's gone before.