My normal soldering iron bit, which is pretty small, would still be too large for this job.
The top bit is an Antex 1mm bit. Pretty standard for hobby electronics use.
Next bit down is an Antex 0.5mm
Below that is my Xytronic 0.8mm that I use for 99% of my electronics work.
The bit on the right is an Antex 1107, 0.12mm bit.
You can purchase these bits from Rapid Electronics as well as other sources.
The upper piece of solder wire shown is standard 60/40 22swg wire.
The lower piece is 60/40 32swg.