I have built several incubators from coolers and they work really well IMO.. I would much rather use a cooler than a very hard to clean Hovabator
the 3-4 inch tape is going to be the easiest to use .. just run a strip all the way around the inside along the wall use some bottled water or rubbermaid containers filled with water to act as a heat sink to help maintain your temps if you have to open the lid very long during incubation
I highly recommend a herpstat .. I am now useing them exclusivly. they are much easier to fine tune to your specific setup I sell them as well as Matt Graybeal