If you want to print as small and precise as possible, you need to print hot and slow with a tiny nozzle. An airbrush nozzle is the way to go. It offers several advantages at once:

• A big problem with small, hot and slow prints is the heatradiation of the hotend and nozzle itself. To get as little as possible heat into the print, the nozzle needs to be as long and pointy as possible. The longer the nozzle, the bigger the distance between heaterblock and the print. And the more pointy it is, the less heat radiation can affect the print.
• airbrush nozzles are very affordable in sizes of 0.2mm to 0.5mm, much more than regular 3d printer nozzles.
• A nice side benefit: the cooling fan can blow better onto the print and "around" the nozzle.

Conveniently, off-the-shelf airbrush-nozzles have exactly the shape one needs for the task. Long, pointy and readily available in different small sizes. But these nozzles are soooo small! Look at the pictures! The tap is M1.7 - to mount this, you need an adapter.

With the airbrush nozzle adapter it is possible to mount these small nozzles in every regular heating block using a M6-Thread. This thread size is used by multiple hotend-manufactures like E3D, Hexagon, Lulzbot, Olson Block, Ultimaker 2+ and much more.