This isn't exactly a "build" as it's rather simple--OK, downright easy--compared to real builds on RCTW, but here go a few more photos of masking and painting fun.
After painting all the FS34107 Olive Drab, I painted the bogies by brush using Vallejo's white. I thought it would be sheer delight to just slop it on as did the GIs sometimes. However, after 55 years of practicing to create clean, smooth paint jobs on model airplanes, tanks, etc., being sloppy caused serious COGNITIVE DISSONANCE. Every realistic little slip was driving me nuts!
Some of the books I have show WWII photos of M4A3s and even two M4A3 105s with rather fresh white camouflage (probably paint, not just whitewash). Curiously, only the sprockets and bogies look to be white; whereas, the rest of the lower hull, road wheels, and even the idlers seem to be left OD. I have used a magnifying glass to check this, and so it seems. Hence, I did so on the HengLong M4A3 105.
Then I re-masked the lower hull and used Rust-oluem white primer on the transmission cover, rear plate, and parts that would have been left on the tank when it was painted.