Nice gun there Bruce, welcome to the BFG club buddy....
Regarding the washer, i cut 2 pieces of an innertube of a bike, works like a charm and gives you a nice tight snug fit.... (mmm that just don't sound right does it..... lol). Derek, regarding the stock, leave it black colour as this is what was Cannon in the films, but it's 6 of one half a dozen of the other, as a brown stock will still get cleared......
Derek, when I carry my DLT-19 on troops, my E-11 is always holstered... you never know if you'll run out of ammo mate.... pack as much firepower as you can handle... hehe