I've got a trusty Marin East Peak XC from 2008, but the rear derailleur's adjustment screws have all sheared and I need to replace it. The derailleur is a Shimano Deore LX RD-M581, but I can't find any exact replacements available.
How can I find a derailleur that will work?
I've found this extra info for my bike:
Rear cogs: 9 speed, 11-32
So the total capacity required is 43
I'm not quite sure if the current is GS or SGS
I've seen some advice that I can could get the right modern Shimano derailleur with 7 or 8 speeds, like an Alvio RD-M4000? I'm not particularly fussed about ultra-high quality or anything, I just need something that'll work well. I'm also a student though and can't really afford to screw it up and buy multiple versions.