'my' setting when not followed by mp3packer is a real CBR320 encoding created by the VBR mechanism
As for 'my' other settings, I use --lowpass 16.7 as I don't need extreme HF and prefer Lame having more data space available for the (to me) more important frequency regions. As for the more defensive usage of - V0 I use my special Lame version with the additional options --ns-bass -9 --ns-alto -7.5 --ns-treble -6 --ns-short 1.
What is the downside to maximizing bitreservoir usage by default?
Sure situations are rare when this is an advantage.