I have never fed fruit. I give crickets occasionally (couple times a month) but cgd primarily. Check their calcium sacs periodically and offer additional vits/Ca dusting on their cgd and crickets especially when they are growing. Uvb isn't necessary in my experience. Sticking to cgd,supplementation and monitoring the sacs are best insurance against mbd imo.
Paper towels make great substrate when they are growing. Once they have some size I switch to cocofiber.