What have others been using lately to repaint D2 Caterpillar parts from the 1950's?  I know aerosol paint is not the best way to go, but I don't quite have the equipment/place for compressed air painting, maybe in the future.

I have been using Rust Check Old Caterpillar Yellow (RC OCY).  I thought it looked pretty close.  I certainly like it. but it could be closer to the "CATS New Caterpillar Yellow".  Rust Check and any other New Caterpillar Yellow is certainly brighter than Rust Check Old Caterpillar Yellow.  Seems in 2022-2023 Rust Check changed their line of paints .  International Red comes in a different can, thou seems the same.  The Red Oxide Primer (ROP) comes in a different can as well.  Have not tried it yet, as still have quantities of the Old ROP.  Seems the RC OCY maybe discontinued, as well as the RC Grey Primer (GP).  I have been using RC GP as primer and then RC OCY as final coat.  I switched to Tremclad Grey primer, but not quite as happy with it.  Seems to go on thicker, and more glossy than RC.  I am just about out of the RC OCY, on my last can, so looking for something as close to the RC OCY.  Sent an email today to RC asking about the OCY and GP. Picked up a can of Krylon going to try that, thou seems like it might be darker.

normal alkyd enamels are safe to do at home. and no real special equipment is needed. cigweld had a tool some time ago called the easy sprayer it was a air blower powered spraygun i think the name for them is a turbine spray unit and it worked well.
what i do if im doing a large job is mix up a empty gallon tin of pre thinned paint this gives a more consistent result and saves time as your mixing once and getting several spray pot fulls of paint. i have a spare lid that id punched 2 holes in so i can pour from the tin into my strainer and i cover the holes with a bit of masking tape.

aerosol can are for little jobs and touch ups.