The Fender Twin Reverb amplifier is well-known for its lush reverb sound.
To make the best of this sound use this technique: Stop the sound of your strings like when playing chords and listen to how the reverb carries on your sound.
You can mimic this sound by using a Boss DD7: Set the mode to 50mS, put Feedback control somewhere around 10 past 12 o’clock ( 12 o’clock is where control is half way up), put the Delay Time control in a similar place and see what sound you are getting. If you feel you are getting drowned in reverb adjust your controls. The reverb sound should enhance your sound and not give you the idea you are playing in a cathedral.
For most realistic sound use the following set-up:
Use a Pre-amp which sounds bright and emulates the Fender sound, put the DD7 after the pre-amp. Use both outputs of the DD7 and connect them to two channels of a mixer. Connect the mixer to a P.A system (or two guitar amps). By connecting both outputs of the DD7 you have more control over the delayed sound: It will sound fuller when compared to only connecting to the mono output.
Digital Delays are bright and to copy the sound of the Twin Reverb this is a good thing. Analogue delays will work as well but a digital delay gets closer to the real thing.
Good luck and hope to catch you soon again,