Buy a cheap set of '''electrician's '''plastic-handled, long-shaft, screwdrivers, then hammer the handles off. You now have a set of long-drivers. Mine are 9" long. I have seen 13" (more $$$).
Also,,, the shafts are often ''fluted'' to prevent handle twist, which may not fit tightly into your driver chuck. My small impact /drill driver works fine with one of the two ''flutes'' ground off.
If your are using a twist-drill chuck, this may not be necessary.
Check the electronics-industry drivers. I found a set of 10inch ''' star '''drivers, used in most plastic appliances.
