Fencer: Yes, of course, how simple can it be? Next point is, that when two players have an "agreement". the set-up has to be made, which means that the original pieces have to stay on their original places and the final set-up has to be symmetric. Furthermore, Black has the oportunity to change two superchess pieces in place when all agrred pieces are set-up. Note that this is a special rule for the corus variant, but we have played a topurnament in Leiden with six pieces and we used that rule there too. Maybe a check-box which a player can select?
In the booklet of the rules, also non-symmetric and even different sets of used pieces for black and white are discussed. The game is very extendable....