Sounds like your doing a lot of research... . But i think you would only need one heat pad if you are going to have a lamp as well. My only advice for you would be instead of the tank why not do a tub? #1 the a 33 gallon is big for a baby bp( i assume you want a baby), you want him to have a feeling of security so a 12qt rubbermaid is more than sufficient for a baby. #2 while your ordering your herpstat(good choice), why not order some flexwatt instead of the exo terra pads. More energy efficient. All this would be a lot cheaper for you and give your little bp more security, not to mention cleaning a 12qt tub vice a 33 gallon tank, Also with tanks humidity is a huge issue where as with tubs not so much. Temps as well.... Just my
Good luck