first, if you press the stem out, you must press it all the way through, in other words the long part has to go all the way through, there is a circlip in the bottom that keeps the stem from coming through the clamp.
second, Emig will make you a set of KX triples bored for the RM forks, it would be a bit pricey but would work
The spacers referred to would have to be split so when the clamps are tightened they would compress the spacers locking them on the clamp, I've done this before but only on the top clamp