Aquarium set up help for Inverts

I'm trying to set up an incubator to use for heating some of my inverts. The main body of it will be an 20 gallon aquarium (30Lx13W) and inside it will be racks so I can place multiple invert enclosures. My only problem is, I've never worked with any sort of heating before. I was thinking about getting Flexwatt but heard that UHP would be better for one enclosure use. I know a Thermostat is needed, so would a Vivarium Electronics VE-100 be good for it (as I need to keep it around 82 during the day and 75 in the night)? Also, so it's not touching bare wood, I was thinking about getting some tiles to place the UHP on and then put the aquarium on top of that, would that be the best?

Thanks for all the help!