Multi mode is not necessary and there is a much more limited number of slots available with it, if you haven’t been using virus multitimbrally you might have been in the single mode, try using the third mode I think it’s called sequencer mode and you can access any patch or init
If you want to record external midi hook up two 5 pin cables, out to in and in to out and be sure to turn off local control on the virus
You can run individual outs from V to OT for sampling/processing sounds separately by selecting the which outs to use for which part on the virus, and if you want to go deeper you could use OT cue out to run an input patch into the V for some virus fx and then back into the OT
Also atomizer is pretty cool, might be redundant with OT but could be used for some extra real time mangling of your OT sequences, you could run OT virus inputs for some master fx to free up master chanel on OT so you don’t have to sacrifice that track, just so many possibilities. Have fun experimenting, it’s got to be one of the more powerful and flexible two piece combos