Possible to connect new stereo with a clock?

Great info guys. So the cigar lighter is always hot. I actually think there is a little tab in the fuse block for that circuit. So maybe just connect wire there and run it to the stereo. I know which wire is for Memory on my unit.

2nd question: the antenna plug is much larger than the new stereo I got. Wont fit. I'd rather not cut the original antenna wire, so is there an adapter that would take me from the large antenna down to the smaller type?

This new stereo I have is a GM-type, and I can find that antenna plug on Crutchfield, but not sure what the larger original plug is called.

3rd question: the new stereo also has a Dimmer for the backlight LCD readout, I know which wire, also it has a ground wire for it. I think the original lead for my old stereo is 2 wire. The one I am using for the switched battery. But the other lead , I think, went to the old radio Light which was dimmable, right? If that is the case can I now connect that lead to my new stereo Dim wire, ground it and have a dimmable backlight controlled by the headlight switch knob for my new stereo?