-20 on your master buss is a nice ref level for sure. I work at both -20 for more pristine things and -14 for a lot of more general work projects and duties. But what is going on with your tracks though?
rms wise sounds like they are all over the place. If you keep your track rms levels constant then the peaks that are in the attack transients will be all over the place instead. Fine. As long as they don't crunch into 0dB FS that is. And they won't because of the built in headroom you have chosen along with your ref level choice.
Tracking at a constant rms level is easier too. Just adjust the input gain on the preamp on the way in for a nice 0 dB VU reading. What could be easier than that! There are often a million questions about how to adjust incoming record levels. This is way simple. It works and sounds great! It is the percussion sounds you have to watch though, and that is when you start using your peak meters more.
I have recently got the Waves Dorrough meter for $29. This is excellent. As well as lots of rms info it displays peaks in a rather incredible manner as well. The free
(was free anyway!) Waves VU meter also has a superb ballistic. Uncanny like the real meters.