Each job needs his own tools.
But there is no strict advice for tools. Here is why:
Long haired roller:
Professional painters love to use the long haired paint roller, because it works fast.
Each applied coat is thick and MagnetPaint needs just this. In general two coats are sufficient with long haired rollers to get the minimum coat thickness of 0.7mm (for more information on magnetism and MagnetPaint: read this).
Long haired rollers will get you a more rougher surface. When preferred: use a window wiper or trowel to smoothen each coat while drying.
Short haired roller:
This is for surfaces for up to 5 m2 the best option. It yields in a smoother surface.
Since the amount of paint per coat is less then a long haired roller, you need to paint 3 coats to get the same magnetic strength.
Finish each coat with a dry lacquer roller and you will end up with a smooth surface. Smoothening with a window wiper or trowel is also possible.
This is ideal for small surfaces. It yields in the most smooth surface, but you even need more coats (mostly 4).
Also, when the paint starts to dry up, it is a great tool to smoothen surfaces that have been painted with haired rollers.
There are different brands and qualities in the market. Please choose the one that delivers the neatest edge.
Use an airless machine with a wide nozzle.
Read more on spraying MagnetPaint here.
Anyone will do.