(much of this post combines with my other posts and theories posted over the last few weeks, just scroll down for more background) 
no growth for 3 months for a juvie lizard? that is not normal or healthy by any stretch of the imagination.
we have seen animals go from hatchlings at 3 and 4 grams, to over 100 grams, in 3 months. they don't have gigantism, but rather, access to all the tools they need to grow and thrive 
you can get animals obese, that isn't too hard. lots of food, poor nutrition, and especially poor heating, and boom, fatsoes. we have growing, thriving Uros, with great body weight and shape, no fatsoes at all 
with proper setup, access to heat (metabolism) and food (calories and nutrition), the roof is blown off accepted Uro "standards" and "new" goals are reachable.
for Hobby, your growth is a problem, because you should see SOMETHING, to be sure. it is supposed to be a growing juvie. you won't necessarily see our kind of results because of the limitations of the setup (i believe), but still, something! and i think your concern is well founded. (i would also start right away with a few fecals and treatment for internal parasites!)
on the monitor side of things, we regularly raise hatchlings to breeding adults within a single year. lots of breeders have done that. with great health and success, over many many generations. when we got into Uros, we thought that there was no reason why we couldn't use the same approach and theory and see the same success. we are only a few months in, but we are seeing the SAME steps and results that we see with our monitors, and everything looks VERY POSITIVE!
the final proof is in the eggs, the reproduction, and hopefully that will come in 2004 : ) we are working hard at that.
we have learned a ton breeding monitors. monitors, uros, lizards, lizards, lizards. more similar than different. apply apply apply!
a soil setup can be poorly executed, certainly. a dry, small, plastic and bird seed setup is also poorly executed. each has a number of problems, detrimental to health, growth and success. a well carried out soil setup is another universe entirely compared to a poor soil setup. simply having "soil" is not the answer! it is about the way it is applied and how the Uros can make use of it properly.
best of luck to Hobby, get your Uros growing!
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robyn@proexotics.com
Pro Exotics Reptiles