Why not sell the RB300 and purchase the RB250 which is a much better arm to mod.A simple weight mod that anyone can do and you have an arm that will better both the RB300 and the RB600.There are 2 bearings on the RB250 not just one with a resonating bias adjuster replacing a bearing on one side as on the RB300.The RB250 also has a brass stem as opposed to a steel one on the RB300.If you want to go the upgrade path the RB250 is easy to obtain and ultimately the much superior arm
