Update, I put a board together to hold the extra components (3 transistors, misc resistors, etc) no luck with the brightness control so far
Edit: lowering the 100k resistor to 430 ohms fixed that
Edit: I looked up the 2n3906, and it looks like extreme limit of base current would have the the minimum value for the resistor at 86 ohms. 100 ohms would give you a little safety cushion.