I usually do my vocal delay itb. In logic i use the stock delay plugins. A quarter, eigth, 3/8, half and dub delay. Tape and bbd style delays do the trick for me as they tend not to procuce litteral copies of the original signal. On top of that, i want delays for vocals not to screw with the directness of the original signal, while also creating depth. For this i use diffirent hi pass and low pass filters on the delay. The longer the delay time, the smaller the bandwidth. For example a half note delay will be bandwith restricted between 500 hz and 3 khz. Whereas a quarter note delay starts at 200 hz and extends to 8 khz. I vary the settings. Also the longer the delay time, the more of the wet delay signal is sent to a reverb.
This way you can use create a lot of depth by using the way that your ears are used to hearing sounds in the real world.
Sounds further away travel to your ears via a lot more reflections, and are also absorbed by various surfaces. Hence the further away a sound, the longer the delay time, the more reflections (reverb) and the more absorbtion ( reduced bandwidth)
This may not be an exact answer to your question but it might help to get the delays right.
For hardware the old bbd delays are really nice. As wel as the old reel to reel delay trick. Pcm70
rocks too for wild modulating delays
Of course you can apply the same principle to hardware delays.
As always, ymmv