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Keith, I can't offer you any advice regarding the dry-brushing since I never done it myself, but would like to make few comments...
You are obviously getting better with modeling and as Terry wrote that is evident from your first posts on the forum up to this time. Also, you are evidently enthusiastic about the whole thing which is also great. However, one does get impression as if you were in some sort of a hurry to finish your every project as fast as you can. (For example, I have noticed that on several occasions with your previous models you said you forget to paint certain parts.) There is no need to repeat what Terry wrote, but do try to slow down a bit and work in stages.
Please understand my comments in well-meaning way as they are intended and continue the good work.