I read that none of the digital meters are as accurate as the old analog VU meters in a trade mag. It went on to say that's why recording studios still rely on the analog meters.
Of course that could have been "fake news" written by a VU meter manufacturer

In the analog days the idea was to run the meters as high as you could including +3 figuring the slight distortion at +3 was better than the tape hiss distortion in the quiet parts.
Digital changed all that. No tape hiss and if you clip even a little bit, it isn't a slight distortion but a terrible one.
Rule #1: Run the levels in PT Pro so they never-ever light the clip light.How high or low after that depends on the source and how I'm going to process them.
Example: If I'm going to add a touch of BBE Sonic Maximizer plug-in, I record at volumes that don't go into the red at all.
If not, I'll let it go into the first or second red indicator but keep it out of the top. Especially if there is a lot of different dynamic levels in the piece. If not, I'm less fussy about that because I can always boost it after the fact.
A nice feature of PTPro is you can always normalize. If you have one peak that is so loud it is making the rest of the track sound soft, you can also boost the volume without clipping the signal. It will in turn minimize the peak.
PTPro Audio is a nice piece of software. It's very good value for the bucks. It's not Pro Tools, but most of us do not need that much.
I've made close to 600 backing tracks for my duo
http://www.s-cats.com with PTPro Audio and I'm very happy with the results.
Generally I'd say if you aren't clipping or lighting the last red indicator before clipping, you'd be fine.
Note, I'm self-taught so if an expert comes and contradicts that advice, he/she is probably correct.
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