I don't grow a lot of cacti from seed but I have done so a couple times with ease. Once with a bbb seed packet, once with a "Kit" and a couple times with collected seed. Although large plants can go long periods very dry seedlings need moisture to germinate and "get going". You could use a commercial mix or make your own. If you make your own probably best to sterilize it. Seeds need to be at the surface, maybe lightly pressed in. I would get the soil mixture to a point it is slightly moist BEFORE planting the seed, than cover the hole pot in a plastic bag or a plastic dome cover. Easiest to put them under fluorescent lights, so the seedlings get enough light without cooking/steaming in direct sunlight in the bag. If the mix is slightly moist to begin with it should not need any watering for some time if covered. If there is a lot of condensation in the bag I would let it evaporate it off and then reclose.

Thanks a lot for that...I think trying with the fluoros would be a good idea as I'm guessing from what you say I cooked them :(