hmm seems like no one has got answers. just to say it again for those who didn't understand. This is not the ceramic heater petshops sell that are like bulbs, but a ceramic plate wich throws heat from underneat.

and what i asked for since someone here told me balls can't have a cool side of 69-71F like i have, is to put one of these and heat the whole vivarium to a tempreture without a tempreture gradient but of course put the tempreture on less then the usual like the guy that sold me mice do.