1st Q can't answer sorry
2nd Q get a thermometer and apply the correct heating needs for your snake/reptile (be careful with heat rocks though, have seen many tragic cases of them going wrong and cooking your herps) that said with a thermostat should be ok.
3rd/lastly Q i set up all my lighting/enclosure and fittings myself. i am no electrician but with time and patience and lots of instruction/manual reading i got it right. if you are not confident with electrics i would recommend a 'sparky'. if you are willing to do a bit of research and give it a try yourself then do it! if you succeed then you gained a new skill and will probably become the households electrician
otherwise you may die of electrocution
