you'd probably be better off handling them to get them used to it, they stop stressing after some handling. Better they stress and get it over with, rather than stress their entire life from not being handled.I actually just spent a half an hour typing, before realizing I should just post a link. This is the best resource as far as Uromastyx care is concerned, other than talking to keepers and breeders directly. (I'm happy to help further if you have any questions). This is a site I have helped out with:
http://urowiki.weebly.com/
Some additional comments:
Please remember to get a fecal done with a qualified reptile vet if you haven't already. Imports often come in with very high parasite loads.
Uromastyx are very stress prone animals. I do not handle any of my uros unless they voluntarily seek it out (usually at the prospect of food.) Rewarding your animal with food when it is bold enough to come close is a great way to build trust, grabbing them or restraining them will simply convince them you are a predator.
While your animal is not in perfect health, I recommend non particulate substrate, such as tile or paper towel. Impaction will not occur with a healthy animal, but it is a concern when dehydrated. To combat this, offer unflavored pedialyte to your uro. It is great for getting them re hydrated.
Had a female Frilled Dragon that was skittish as hell when I got her and I gave her a cage 10x bigger and handled her for a few minutes a day, She was eating out of my hand in no time, as opposed to freaking out everytime I reached in to clean or change water.
Ultimately this decision was made after I talked it over with a handful of other professionals weighing the pros and cons of handling/stress vs. no-handling/stress and we all agreed it was better to get them used to you