I have the Challenger Bullpup, so there might be a difference in shim washer size, but here goes:
I made a washer out of a steel for additional hammer weight and only a little additional spring pressure. My washer is .835" o.d. by .560" i.d. and .118" thick. It weighs 67.3 grains, nearly the same as four of the AEA aluminum washers. AEA washers are only a few thousandths larger and .080" thick each. The slightly smaller dimensions were made for clearance for easier removal because the aluminum washers were a tight fit and required complete disassembly to remove. I also found that the stock configuration from the factory produced more consistent and tighter shot string. So after various testing of the AEA washers and my steel washer they are not currently installed.
As far as a depinger goes, there is a guy who successfully installed a section of wire loom ribbed plastic in his AEA. This wire loom is available at auto parts and hardware stores. This is probably a better solution than a brush because the brush has the potential to loose bristles after a while.