Fuel sender flange-washer or proseal

[avi8tor50]

Getting ready to seal up the flange for the fuel sending units. I've read the posts that discuss using the rubber gasket included with the SW kit vs Proseal. Was thinking about using proseal on the inside of the flange that is visible thru the hole in the fuel tank end flange (looking from the inside out). Wanted to put some proseal on the screws. Was wondering whether it should be placed on the ends of the screws as they come thru the nutplates or on the screw threads (remember they will be going thru the washer-will proseal work in that scenario?). Another thought would be to just disard the washer and proseal the sender flange on both sides and do the screws as well as others have done. Would welcome any thoughts and opinions.