Ebay and live auctions are weird and unpredictable. You can never be sure that the people who most want the item are in the bidding. If at least two of them are, the sky's the limit. If not, and there's no reserve or the opening price is low, the seller can really take a beating. That wristlink that sold for $516 on eBay in 2011, I never saw that auction. Does anyone have a screenshot or other copy of it? The same prop sold through Profiles in History in 2005 for $1200, from a catalog estimate range of $800-$1200. OUCH!
The only *possibly* show-connected gummi bear handlink prop whose sale price I know is the weird green and blue one that was misidentified by Profiles in History that sold for $3000, from an estimate of $1000-$1500. In my opinion, that piece was at best a non-screen-used prototype, and at worst possibly someone's homemade replica. I give Profiles in History a failing grade for their poor research on that one, and shake my head in pity for the bidders who apparently took what PiH claimed at face value without doing their own research, and drove the price up that high.
I have not had any luck getting exact measurements of a screen-used GB HL. Mark Dickson wrote at the Replica Props Forum that he made a tracing at the same time he took the photos he posted, and that he sent a copy of that tracing to another RPF member, but I was unable to get a response from either of them. I did get a response on a different topic via a different site from Deborah Pratt about her original prop. She said it's in storage somewhere and I got the impression that she doesn't want to be bothered to dig it out for mere fanservice to one person, which is completely understandable, so I probably won't ask her about it again. If my replica project turns out well and opportunity presents itself, I would offer to restore her original (which is in rather sad shape) but getting that opportunity doesn't seem likely.
So the best I can do for now is photogrammetry -- take the best available image (the Mark Dickson front view photo), make multiple corrections to it (lens pincushion/barrel distortion, rotation, tilt/perspective, etc.), then scale it using known dimensions of some of its parts, such as the LEDs and the battery. Since the last time I scaled it, I have obtained some LEDs that I didn't have before (the CP-56/57 equivalents) as well as the correct batteries. I've also made new discoveries and changed my mind about a few details, so I need to go back and do that whole process again. I think I can get accuracy within a couple of millimeters that way.