What's a good time scale to set? I know the default is 20 but I was thinking of dropping it to 10. I'm also using Total Realism Basic Needs so I will give extra bonus points if someone can recommend a time scale and the factor to change your needs (half as often, 1/4 as often, etc.)

Can any of us really tell you what your ideal value is? Personally, I'm totally satisfied with the default. The best way to find what works for you is simply to change it and play for a few hours and see how it feels.

I also am pretty satisfied with the default 20. I used to set it around 15 in Morrowind and Oblivion, but I can't say that I've noticed much of a difference between 15 and 20, so I leave Skyrim's time scale alone.

I don't use "realism" mods though. That may (or may not) make a difference.

I set the timescale to 10, it just seems to work better for me. Gives the day a more "real" feeling, but again, that's just me. Played once with it set to 1... I don't recommend it. Ten is a good compromise.

8 seems to be just about perfect for me.

With a timescale of 20 I found it a bit annoying that I would go on a quest, walking across a relatively short distance and day and night would pass so quickly.

I'm not sure how the Total Realism mod works, but with Imp's More Complex Needs and Frostfall, the needs/hypothermia rates are adjusted automatically to compensate for whatever level you set the game timescale.

Is the ability to set the time scale available on PS3, if so how?

Unfortunately, no, it's set by console command "Set timescale to X"