I will second Ian Scovell. He did a stellar job on my 6x7 b+w reverse processed transparencies. I've currently also got a number of 6x17 panoramic b+w reverse processed transparencies waiting to go to him (funds a bit low at the moment after moving house). He uses 6x17 format himself. He also scans Colin Prior's Fuji GX617 panos so has a wealth of experience...
He's very helpful - email him for a discussion about your scans.
If you're wanting to give your 617's a go yourself on an Epson (I've got a V700), use these custom holders, the 120 ones + the anti-relective glass are great for 120 film, and keep 617 flat.
http://www.betterscanning.com/
But I'm not great at scanning or interested enough in it to learn more - my own scans are for basic archiving etc. Master scans are sent to a pro to get done properly...!

). He uses 6x17 format himself. He also scans Colin Prior's Fuji GX617 panos so has a wealth of experience...
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