We have just gone through this Tobius, when we pull the brown wire it is like taking one cylinder out, the higher the elevation the worse it gets.
Above about 2500 meters we leave the brown wire connected as the engine does not ping at the higher places.
We have run the 90 without pinging except under heavy throttle passing a truck or something uphill, we only get a couple of pings then quiet so it does not seem to be a huge issue.
Thanks for the heads up on the fuel, with fill the 38 liter supertanker to the brim with good stuff to allow mixing.
Re your fuel pump, it should ticker every time, our earth wire to the points fell off so we fixed that, just last night we re fitted our DR Bean board.
If your points are stuffed we have a spare set, we also have a spare DR Bean board, you can have that which will fix all but we would want a replacement to keep as a spare.
Let us know