First off, I love our hovabators. They are cheap, control a constant temp within 1 degree and so far we've hatched all of our leopard gecko and uromastyx eggs in them without a problem.
We've always used the small gladware containers...they only really hold maybe 6 uromastyx eggs each and you can only really get 4 container in there so....the way we do it...you'd only get 24 eggs in the hovabator...which is kind of a small amount.
Using your idea should be perfectly fine...I don't see why you couldn't fill the whole hovabator up with vermiculite and add a container of water...the hovabator is meant for chick eggs and has a plastic tray in the bottom meant for water...I very much doubt you'd short out anything because it's meant for high humidity.
We've also incubated leopard gecko eggs, tokay gecko eggs, and veiled chameleon eggs using just an old fish sytrofoam shipping box (or a styrofoam cooler) and put a vase or fish bowl in the styrofoam box, filled with water and put a fishtank heater in the container of water. You can turn the heater up or down to control the temps. But get a digital thermometer to make sure you've got an acurate temp.
With the styrofoam cooler incubater you've just got to take into consideration that it get VERY humid, and the fish tank heater is not as accurate as the hova's wafer at controling temps...the fish tank heater can only really stay with 3-5 degrees of temps. Also the fish tank heater's max temp in the box I use really only makes it to 86 degrees tops....so this method has never been used with anything like our uro eggs or bearded eggs that require higher/dryer temps.
Hope this helped.
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Chris Vanderwees
E-mail Me
1.3.0 Veiled Chameleons
3.2.0 Corn Snakes
1.3.0 Tokay Geckos
2.2.0 California Kingsnakes
1.3.0 South Florida Kingsnakes
1.1.0 Albino Sonoran Gopher Snakes
1.5.0 Leopard Geckos
0.1.0 Green Iguanas
3.4.0 Mali Uromastyx
0.0.1 Savannah Monitor