Stram,
It very well might work, though I've never tried it - just experiment a little with differing amounts of talc in the mix.
Personally, I wouldn't bother - there are so many very good dullcoats for sale out there.
Humbrol, Testors, Model Master, etc etc etc .
They work great - why risk messing up a great model when you can use a tried and trusted dullcoat?