How the West Was Won - Mills
Wake Up Bomb -
New Test Leper -
Undertow -
E-Bow The Letter - Buck
Leave - Berry
Departure -
Bittersweet Me -
Be Mine - Mills
Binky the Doormat -
Zither -
So Fast So Numb -
Low Desert -
Electrolite - Mills
I assume How the West Was Won was started with Mills with Berry having a key role. Similarly, I suspect Leave started with Berry and then was expanded with Buck. I’m assuming Mills started Electrolite with piano.
I would be very surprised if “Departure”, “Bittersweet Me” and “Low Desert” were not started by Buck. Note that this is purely based on my suspicions 
Please keep posting these! loving it.
How the West Was Won - Mostly Mills & Berry
Wake Up Bomb - Mills
New Test Leper - Buck
Undertow - Mills & Buck (the Millsey-chorus origins are “Rocker W Vocal”, from the Monster demos)
E-Bow The Letter - Buck
Leave - Berry (Just Berry)
Departure - Buck
Bittersweet Me - Buck
Be Mine - Mills
Binky the Doormat - Buck & Berry
Zither - Buck ( & there’s a chance that Bill was involved…)
So Fast So Numb - ?
Low Desert - ?
Electrolite - Mills
I think, maybe more so than any other album from Out of Time onwards, Hi-Fi might have been very collaborative. Given that it was written on tour, a lot of these songs would have been ‘jammed’ at soundchecks.
Undertow’s an interesting one. Parts of it definitely stem from that Monster demo. Guitar-wise, it sounds like pure Buck. But it’s driven by that amazing Mills bass line. What came first?!
As with the other albums, I kinda think it was mostly Buck to start with. The exceptions being:
How the West Was Won - Mills and Berry
Maybe Undertow…
Leave - Berry
Be Mine - Mills
Electrolite - Mills
Peter Metioned in a 96’ interview that he wrote the verses to Undertow with Sonic Youth in mind…
Do we know that Buck wrote New Test Leper? It seems somewhat similar to some of the acoustic songs Mills wrote.
These answers I would love to know!
Oh yeah, he mentioned it, several times. also - in a 2001 interview Mike talked about the Wake Up Bomb, said that he wrote it and wanted it to be the first single…
I think I read somewhere that Berry had the acoustic guitar intro to “Leave” and Buck fleshed out the rest, much like “Man on the Moon,” where Berry had the open C to D slide intro, and Buck fleshed out the rest. I highly doubt anyone other than Buck came up with the e-bow parts that are the backbone of “Leave.”
Bittersweet Me screams that Peter wrote it. The arpeggios in the verses are pretty clearly his trademark. I’d be very surprised to learn that Bill or Mike wrote that one.
It’s possible, but almost everyone in the band referred to Leave at one point or another as “a Bill song”, they did it with Perfect Circle as well - another full-Berry song, and not with MotM or Driver 8 which are semi-Berry songs…
Scott came up with the Siren for leave.