In addition to the IR feed through monitors you can use the OX's attenuator to mix in your amp at low volume through a 1x10 or 1x12 cab (Greenback works well). This creates a low volume wet/dry/wet rig that sounds awesome at low volume.Get a nice reactive load with IR's like the Suhr Reactive Load IR or UA OX. Use any amp you want and crank it at conversation volume...
I use a Suhr PT15IR into a Stienberg UR22 interface, into JBL LSR 308 monitors... Sounds like a cranked Marshall!
* With the Suhr RLIR you can use the Un-Filtered out into a low-wattage power amp pedal (EHX, Quilter, etc) to bring your cabinet in.