That Deluxe Reverb pedal is not a digital reverb pedal as such, it's an amp modeling pedal that contains reverb... totally different. You won't get good results with it unless you're plugging into a totally clean amp I don't think - it will sound terrible either in front of an amp with distortion, or in the loop.
If you want reverb on your Dual Rectifier any *normal* reverb pedal should work - eg a Boss RV2/RV3/RV5, EH Holy Grail etc - and is best in the loop. There is a problem with some pedals in that the loop is parallel and can cause some latency issues, but I don't think the Boss pedals (certainly not the RV2 and RV3) do this since they keep the dry part of the signal analog.
If you can't get a good tone with the pedal at 'normal' settings, try it with the pedal mix set to full effect and use the amp's Mix pot to control the reverb level. That will definitely work since only the reverb is being added.