ROY ,
It's never too late to add th Chips ! Although ... you may want to consider this though . after adding th remaining chips , instead of shooting a flat coat, shoot a Semi-Gloss coat ( Vallejo Satin or similar) That way it'll give th washes etc. something to run on. Meaning - on a flat surface, the surface is rough & washes tend not to want to run around the details , a Gloss coat is really smooth ( that's why it's very shiny , slick to reflect the light) this allows the washes to run almost totally off of th model , a satin finish is somewhere in between , it allows th washes to flow & get into th details of the model.
Now I really didn't pay too much attention to this until MIG suggested it when talking to him about His AK fx , etc. So, I tried it & lemme tell ya' I was really impressed that it really helped & I could see th washes running around & doing Their job. after which I went about dusting up the model .& the Satin wasn't really a glaring issue. Besides , after looking at some examples that MIG showed - Tanks aren't really Flat , they have a touch of a sheen to them. After I applied th pigments I didn't even seal up the model.
Here's an example. This is an Elephant that I did for the Spring contest & followed th process as I mentioned above.
AS you can see there's no real sheen . This is what worked for Me -
1) After painting the Elephant , I shot a gloss where th decals were to go , then did some chipping & dry brushing
2) Sealed it up with 2 misted coats of Vallejo Satin ( it'll cloud a touch , but once it's dry that "haze" disappears)
3) Went back & added a few more chips & dusted with pigments - th light dusting, I think brought everything together and still left th model interesting & Authentic .
I'm not saying this is the absolute/ correct way , it worked for me & allowed th wases to flow. I used the AK Interactive Grime for Dark Yellow Vehicles, thinned to a wash ( I used Turpenoid , but would recommend Their Mineral sprits , as it dries faster). I also used th same to streak th Elephant , which gave Me a Big canvas to work & I was really happy with th results.
Just My $.02 (USD)
so , just a little food for thought.