Hi Jeremias. I have been doing this for some time in the “live feel” way that you mentioned. I don´t know if this is the more efficient way, but I will give you my experience.
Important #1: DAW’s tempo (eg: 90 BPM) must match BB’s tempo. With this you can edit after any part very efficiently.
Signal flow:
BB (stereo output) --> M-Audio Fast Track Ultra (stereo inputs)
M-Audio Fast Track Ultra into Macbook Pro.
I am using Garageband as DAW.
In parallel, I am recording the guitar into audio interface while drums are being recorded. This is just to have a reference. (I would record the final guitars after having drums recorded)
Important #2: it is inevitable that there will be tempo mis-match according to when you press record button on DAW and when doing the same on your BB. Even if this can be mostly unnoticeable to your ear, doing it as closer as you can to the tempo on DAW, will make things A LOT easier when editing after recording BB/guitar. I mean cut, copy/paste, etc.
Probably there is a easier way to accomplish this through Midi like pressing a button that starts recording DAW and BB at the same time. Don´t know if latency issues will appear doing so. I have not figured any of this out yet. (Maybe someone in the forum can help with this topic?)
So, what I do is:
- Press the record button on DAW with it´s metronome on, so you can hear the beat.
- Then press start on the BB just in time with DAW´s metronome. Record 1 or 2 measures and stop recording.
3)Then check visually how close are the wave sounds on the drum beats to the divisory lines in DAW´s measure. Make zoom-in to make this as close to “correctly” aligned as you can. Probably this will take some iterations until you get it right.
Hint: it is helpful to set intro`s in BB as just the click instead of a drum fill. (Settings–>“Mainpedal”–>Intro). With this enabled, it will be easy to check if BB beats matches DAW measure beat-divisions. (making editing easier after recording as said before)
- This will be your track that contains your first couple measures which will be very right aligned to DAW divisory-beat lines.
- Mute this track and create another tracks (BB, guitar, etc) to just record without any of the previous mentioned concerns.
- Record the entire song (BB and guitar and whatever you want) on DAW. No concerns here. Why is this? Because after recording the entire song, you can just do some cut/copy/paste of the “perfect” start previously described (steps 1-4) and insert it at the beginning of the entire song track. Adjust to taste.
Other idea would be to record every part/fills/transitions/intro/outro of the BB song you like and then cut each one and paste on different DAW´s tracks. After that, you can copy/paste and put them in the order and times you imagine for the song and finally record guitar. This is less “live feel”, but can be useful if you want to mix different sections (or even different time signatures) of different BB` songs.
I think this is it. It can seem to be complicated at first, but you will see it is not.
Hope that someone can tell us something about a Midi setting to start recording DAW and BB at the same time 
Cheers,
Vicente from Santiago, Chile