One other point about your "see-sawing".... Might as well wait till you get the new blades to find out, but if the blades were that far off, and your getting that vibration, and you bought it off ebay (ack!), chances are probably good that at least your feathering shaft is bent too, perhaps even the main shaft.... Try starting it up and spinning the head (NOT REAL FAST!!!) without the blades installed... If it's shaking and vibrating then the main shaft is probably bent too... If the main shaft is bent I can pretty much guarentee you the feathering shaft is too... Even if the main is okay, probably not a bad idea to replace the feathering shaft anyway...