I've got an older Kahler tremolo I'm considering selling, but before I do I was wondering if there are any advantages/disadvantages to the original Kahler tremolo vs. the new 7410 version? Do the original versions retain any of their "collectible" value now that the new ones have been out for a while? Lastly, has anyone ever heard of a locking nut for bass? I've never seen another one. Not even sure how well it would work w/o fine tuners - maybe a better idea for a headless bridge?