Bufflehed, for multicolor camos using Sillyputty you have to think backward. Whatever the last color they sprayed IE yellow, green etc, you spray first. Add the Sillyputty to cover that color, in the typical case of a Japanese tank perhaps the yellow stripes, Then spray the next color, perhaps green. Mask again, over the first masking and complete the process until almost the entire subject is covered. In my case, for my 1/72 Ha Go, I hand painted the yellow stripes but it was so small I could get away with it. Leave the previous mask on and apply more over it for the next color. It's a trip when you remove all of it at once.
I hope this is new information for you and it helps. In your case it looks like a yellow, brown, Lt brown, green sequence
