Ambient heat panels/heating

[Brently]

I am trying to gather as much information on heating as I can before I build my next enclosure. I have a 4ft boa that I am planning on building a large life enclosure for in the not very distant future. I am planning on making it a large show piece with decorations and what not. I am curious how the pros plan and layout their heating before building the enclosure. I would like to use heat panels but have no experience with them. I am planning on making the enclosure 6ft long minimum and 3-4ft deep and high. All this is subject to change. But how do you know what elements to get or is it just a crap shoot? Your experience would be appreciated.