Level of low shelf on targets, is very low bad?

[JM1]

I plan to experiment and listen to results but looking for some guidance on ranges that create well conditioned filters.
Assumptions are using minimum phase targets at low frequency.

It seems that a low shelf at -30 to -40 dB produces a fast settling step response e.g., below 10% at 1/high-pass-corner-frequency.
Lower shelves, say -70 dB take longer to settle, and more group delay.
Deep shelves, say -100 dB do not have smooth curves in the 1 - 10 Hz range. I assume that deep should be avoided.

My question, is there any benefit to setting the low shelf lower than about -40 dB?

 

[juicehifi]

I believe it should be OK as long as it is levelled out close to 0 Hz and close to FS/2. A steep drop at the extremes creates some brutal phase conditions that challenges the math....