Here’s a guitar tip stolen straight from Joe Satriani’s pedalboard. (Satriani just happens to be here right now, playing a workshop/concert for lucky local customers!)
Use two delay pedals, with one feeding the other. Set one for a 300-400ms time, with a good number of repeats, and mix it so it provides an “ambience,” similar to a reverb.
Set the second delay for 650ms of delay time, choose a darker delay sound (if you can EQ the delay repeats), and mix it fairly strong.
The combination of the two will create a powerful wash that will sit behind the main guitar nicely, providing tight ambience, with a good delay effect on top that fattens and fills the sound.
The almost random interaction of the two delay times doesn’t create a true “rhythm,” so there’s no need for tap tempo.
Try it, it works great!