Sorry, I don't take very good pictures on the run. I have a Vallejo base coat - clear cote - Hairspray - water-thinned Tamiya white brushed/dabbed on. I used stiff and soft brushes to remove the whitewash before the white dried. I regret not doing my usual complete build prior to painting so ignore the unfinished hatches, etc. Any whitewash suggestions welcomed.
I don't have any real answer's but i would try putting your whitewash on with ether aairbrush or a paint brush as i feel that you have more control and both of those way's were how they did the real thing
I've included a pic of my whitewashed m4 105 which i sprayed on the white and used a brush to do the chipped edges .i hope this give's you some help, have fun with you'r project all the best wayne