Before I take a stab at helping you, I've gotta ask, are you trying to tap the actual length of each delay with your foot? With early tap tempo delays, that's what you had to do it, but dude, it's so much easier than that now. Before, you had to have perfect timing. Now you just tap the beat of the song and let the delay unit figure out the rhythms from that. It's a MUCH better way of doing it, and I'm about 99.9% certain you should be able to get the sound your looking for this way.
Anyway, I found a great analysis of U2 delay sounds at the site below:
http://www.amnesta.net/edge_delay/streets.html
In "Where the streets have no name", there are 3 delays. The first is a 20ms pre-delay that is probably not created created by a delay unit at all, but by microphone bleed from 2 amps setting 20 feet apart. The Edge did this a LOT. The other two delays are created by his old TC Electonics 2290s, one at 3/16ths (dotted 8th) and the other a 9/32nds (weird). I personally can't here the 9/32nds delay. The most vital is the second delay, so try this…
Delay A set to the shortest delay posible, say 1/64th or so, mixed in lightly with maybe two repeats. Delay B set to a dotted 8th mixed in higher with 2 or 3 repeats. Skip the third delay. I can't even hear it. These settings should get you close enough for any sane person to find acceptable.
