Specifically for the Viper I use a side-mounted VKB Gunfighter MK.II w/ SCG grip - see photo. I've added a #50 spring for pitch, and a #40 spring for roll, and that gives me the heaviness for how I interpret the Viper's stick to feel - short of a force-sensing base. I don't seem to experience any deadzone issue, as the FBW PFM feels snappy enough to me.
I also have a center-mounted Gunfighter w/ MCG grip and stick extension, but I don't even think of using it for the Viper, as only a short throw stick would feel right with this module.