Shlind, I just spent the morning following your path. I have never used BIAB to split stems. I just never needed to. I have tried other splitters and found SMP to be comparable with nothing else being superior. But you Bass track made me try BIAB since I am just off a project where the bass was a real challenge. So here is what I have concluded:
1) BIAB splitter was not as difficult to operate as I thought it would be, my bad (I found the 2025 Simon Video). But once I got the Bass Audio stem from BIAB on my current project, I did not continue on for tempo mapping and chords - this process still looks too difficult and at this time I don't need it since I have other workflows.
2) The resulting bass stem from BIAB was not good! While there were no significant drop outs, the bleed over from other stems was way to obvious.
4) Even the vocals in BIAB had bleed from the strings. Which was the same issue in SMP.
3) So I don't doubt what you showed when you compared BIAB with SMP. I am just concluding that every track has its own challenges.
4) By the way, I have not been able to "combine" the stems from BIAB into SMP as you did (Otherwise, I would have pasted the pic). I am still missing something which I may figure out in time. I must have to due with the "settings for folders". the defaults seems to be a mess using "a network drive" which I avoid.
5) I have solved the Bass problem in past projects by using the midi chords from SMP and sending the midi to EZBass where I isolated the bass notes from the chords. That worked great.

Thanks for suggesting this workflow. I am always looking for how to improve my music making.

Dan

BIAB – 2025, Reaper (current), i7-12700F Processor, 32GB DDR4-3200MHz RAM, Motu Audio Express 6x6 - My SoundCloud (Tip: No need to create a SC account to hear music - just hit ESC ).