I use only a linear uvb bulb (reptiglo 5, I can't get reptisun) on my babies, no basking bulb. The linear bulb produces enough heat for them to stay warm enough. I raise all my babies in 10 gal. fish tanks until they are large enough to be moved to small screen enclosures and have had many...
Welcome from Ontario Canada. You're going to love this site. It has so much information on it that you will be up and running in no time. The forum has some very knowledgable keepers that can help you with pretty much all your questions you may have. Enjoy your Cham experience...it's very addicting!
Even with a laying bin, I have had them just push out eggs all over the cage floor. Others will lay in the bin as expected. If the eggs are unfertilized, than I dont think it matters if they just drop to the bottom as you will be discarding them anyway.