Chosing brushes

These are the brushes I'm using to paint the Canberra's decks. For most of them, the Number 1 Humbrol is ideal. There's a lot of dodging in an out of deck fittings and working up to, but not up, walls.

For the larger and clearer deck areas, I've been trying a Trumpeter F01 flat brush. In theory it ought to be idea and as a tool it's lovely. The resulting paint comes out very thin though. Maybe my tin of Humbrol is a touch thick and doesn't flow off the bristles as well as it does from the Humbrol. Maybe it is actually better since the coat in thinner.

I don't know. Any comments ?

Please don't say "Go and buy some sable" - I have a few and while lovely, I don't think they are as lovely as people say for model making work. They cost a lot more too, which is a consideration when working in tight spots and poking the hairy bit around. I'd rather b****r up a cheaper brush thanks.