Not a brush painter on models Keith. But I am, to boast, a top notch house painter as I cannot abide rubbish house painting.
So this is my way which I am sure crosses into hand brush model painting. But just to say that an air brush will give you near perfection. Only two thin coats of paint needed rather than the 4 with a hand brush.
First it is better to put on each layer with a very thinned paint and not to full a coat just enough to cover. Do not go back over the surface covered to fill any thinness as by that time the thinners will be evaporating and then cometh the brush marks. Keep the mixture stirred all the time which ensures the brush is kept well moist all the time right up through the bristles.
Wait to dry most thoroughly. If you can see brush marks any where then a 2000 gauge wet and dry but the surface must be well cured. Just before any further coat use a tack rag to get rid of dust and hairs. It is a patience in time affair. Also wash your brush before each coat to get rid of rubbish. Before starting finally dip the brush in thinners the worst thing that can happen is for the brush to dry in the middle with paint the thinners in the brush will keep it moist.
Mentioned recently a guy who used to show his stuff on this forum. He only built Lancasters and hand brushing his finishes were something to behold. Not sure which paint you are using. If it was me I would use Vallejo
Model Air. Although an
airbrush paint it is very forgiving and levels out . Needs additional coats compared to say Vallejo Model.
I have tried the above and it works. But the simple answer is Airbrushing.
Laurie