RetroSound install question

[NC67Chev]

I made the splurge and got a Retrosound unit for my '67. I have the new speaker and radio installed in the dash, but I haven't done the wiring yet for power (Red), memory (Yellow), and ground (Black) wires. My questions are:

1. Power - Is there any reason I can't splice in to the original red wire? The original radio power wire doesn't appear to be fused....it looks like it just plugs into the fuse box. If I do this, I guess I should put an inline fuse?

2. Memory - I know this needs constant 12v, but where is the best place to wire it to? I've heard that the cig lighter wire is good to use, but mine didn't have one installed. Ideas?

3. Ground - Does it make any difference as to what I attach the ground to? The easiest would be to attach it to the radio support.

Thanks for any guidance you can provide.