I have enclosure that size, i use a big zoomed pad other (yes other the wood) and inside i have 2 neon 4 feet around 20watt, (be sure that your snake don't crush it, put some protection). Neon don't get hot enough to burn your snake if he is too small to crush it. I have 2 4inch vent one close to the top and on close to floor. So inside temp on day 92F with some coolers spot. On night 92F on the pad and 78F to 80F for the rest.
If you want to take a look try this.
http://www.ssnakess.com/forums/showt...&threadid=8184