The insert sends are at a fixed point in the signal path (effectively post preamp+pol inv.) The DO point is movable to different points in the signal chain, but is global for all channels. The DO tap point is also where you will feed your ME1s and and FX units configured as channel-return. Which one you should use would depend on what sound you want in your recording. Most people record post preamp then use the DAW to add in FX and processing later, so the Insert-send position would make sense for this.
If you wanted the recording to include your QU’s processing, you’d need to use the DO option and move it to the appropriate spot in the signal chain.
If you do choose the DO option and move it, you need to be aware of what that will do to your ME1/FX sounds, which may or may not be a moot point.