My husband and I are preparing to get a rack built this week, and I'm finishing up looking at plans and instructions so I can get it all drawn out and then we can start building!

First question: Does there have to be some kind of gap in the back or sides of the rack?
I'm noticing a lot of pictures of racks show an open back or sides. I don't know if this is just how they were built for simplicity, or if this is required for something like ventilation. I do see where a gap of some kind is useful for running wires, and will incorporate this into our design, but if it is not needed for ventilation, I would like to make it otherwise solid and enclosed.

Second question: Is there any one brand of heat tape better than another?
I see flexwatt heat tape recommended a lot (http://www.bigappleherp.com/Flex-Watt-Heat-Tape), but while searching I also found something similar from Reptile Basics (http://www.reptilebasics.com/heat-tape). They look to be the same thing, but I want to make sure before I purchase something and then regret it.

We are planning to build our rack from melamine, and it will be built to accommodate the 41qt tubs we are using while still fitting in the space we have available for it. I'll use a space heater in that room if necessary to get the right ambient temperatures, and then the heat tape under the tubs themselves. We are currently using a hydrofarm thermostat, but are planning to invest in the more expensive proportional thermostats as we get this rack built. I think we'll also invest in additional dimmers or thermostats as back-up, just to be on the safe side.

So my third question: Is there something I'm forgetting or should consider?