I think I understand what you're wanting to do: you might have an amp block with x set just the way you want it, and now you want to pull settings from a different amp block's x or y and save to ONLY the y side of your amp block (a global amp block, in your case). In other words, you're hoping to save *just* x (or y) of some unlinked amp block to a global block without overwriting 'y' on that global block. Is that the situation?
I can't remember: does saving a block into the Blocks Library save both the x and y of a block, and then restore both x and y into a block, or does it only apply those settings to the block that you're on? If it only restores to either x or y, but not both, then that may be a way of accomplishing what you're asking (in multiple steps). I kind of think the Blocks Library restores the entire block though (both x and y). I'm not sure if there's a way to copy/"paste" only the x or y side of a block into another block. I wish there was a way to do that.
