Brett--
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There is a second reason to buy better tubes: more solid construction. Many folks who do a lot of macro, including me, use the Kenko set, which is metal, has contacts, and can be stacked in any combination, giving you 12 to 68mm of extension. There are some cheaper ones that are also metal and have contacts, but I have no experience with them.
A 1:2 lens even with tubes may not be enough for big bug eyes. You will be getting close to 1:1, depending on the length of the tubes, or a bit higher. That means that a big bug's eye, say, 4mm, will be only 4mm on the sensor. Still, it may be a good investment, because if you get hooked on macro, you can use the tubes with a 1:1 macro lens if you ultimately buy one.
I'll post a few as examples. Keep in mind that the effect of extension decreases with the focal length of the lens. Both lenses are 1:1.
Dan
60mm macro, 68mm extension. This is well over 2:1. My fingernail will give you scale.
100mm lens, 36mm of extension: