I am covering safety as a third post to give context, despite the fact that it is the primary concern. A must for starting a project like this is the appropriate standards. This sort of project is done professionally, and is approved by fire departments, assuming codes are met. Many locations seem to use one standard in specific from the National Fire protection Association NFPA 160: Standard for the Use of Flame Effects Before an Audience
This standard goes through a wide variety of aspects which need to be included in a design, and used during operation and site setup. The reason this is the appropriate standard is that this is a flame effect. It is not an explosion, instead a controlled open flame. It is also appropriate because there are operators, but there are also audience. In my case, the wedding attendees, as well as arguably the couple are audience. I will use this as a guiding principle, meeting as much of it as possible. An older version of this document is available as a pdf elsewhere on the web for those who need it. This is a Group III flame effect, though aspects of other classifications also are applicable.
Beyond what is covered in this standard, there are several safety aspects of the electronics which will be discussed in their design.