I've been doing this with the Headrush FRFR-112 and the Volante. It sounds great, better than I expected. It's not going to sound exactly like an FX loop which puts it after the preamp but before the power amp and speaker. It's going to sound more like if you record your guitar and then add delay in post processing, which is actually fairly frequently done on records. It lends a touch more clarity to the delay since it's not getting distorted by the power amp or speaker or microphone, etc. You're essentially just using a studio trick in a live way given the nature of having a full amp & cab sim going into effects, then into an FRFR. I'm going to experiment with the Deco today, which would be like running a recorded guitar into a reel-to-reel for some studio ADT-esque magic, which is a more realistic application for the Deco anyway.