The delay sounds you are trying to copy are 80's Analog pedals and tape echos from the 70's... That being said a Digital Delay like the Boss will sound much cleaner, the repeats will be much crisper sounding over the older units the bands you want to copy used in their day...
again That being said there is nothing wrong with using a great delay like the one you have... Most players use them these days, it is a great digital unit...
In the 80's Delay pedals had less repeats and delay time so cut back a little... I'd say set it up so the repeats fade out compeletly by the 3rd repeat.... Then it is up to you to find the speed of the repeats for each song you want to copy... just play with the delay until it is repeating in time with the recording
also cut the volume of the repeats too... older units did not repeat as loud as modern units either