These are my new babys...

I also own two others....

My recommendation would be to stick with fresh greens that contain a healthier balance of vitamins and minerals and better Ca:P ratios such as escarole, curly endive and dandelion greens. Always look for at least a 2:1 ratio in all of your staples.

I would definitely suggest staying away from insects especially at this young age.
A four years field study on ornate uromastxy showed that neither adults nor young intentionally consumed insects in the wild. This study concluded that these animals are totally herbivores. The feeling by quite a few professionals in the field is that most species of uromastyx are true herbivores while a few could be considered omnivores.
While an omnivore may be able to consume lower levels of animal protein, a herbivore cannot without suffering eventual organ failure. Why take the chance?
There are other concerns with feeding crickets to young uromastyx such as lodging and the inability to breakdown the keratinous outer body.

D3 can be toxic if overdone and young animals are especially susceptible due to their size. An excess amount of D3 in the system can produce results and symptoms similar to MBD. If you do decide to supplement, I would recommend using it very sparingly several times per week. As long as you can provide a close source of uvb 12-14 hours per day, the uromastyx will be able to utilize the calcium in the healthy greens above that I mentioned. In addition to a good UVB source, I take my hatchlings outside for natural sunlight 2-3 times per week.

I would recommend that the basking temp go as high as 120F but the ambient temperature should not exceed 100.

I suggest strongly that you not readily take the first opinion you hear when it comes to your uromastyx. If that opinion should be wrong, your animal will suffer. Do research, purchase books and talk to breeders and people who have raised uromastyx for years not the people who import just to sell. Also use common sense as there are a lot of people keeping uromastyx that are not qualified to own a pet rock. Just because someone has owned an animal for a year or two, does not mean that it is healthy or that their husbandry practices are sound. Research, dig, and then research more.