The Plustek is nice, I borrowed one a while back. I use the v600 because I shoot mostly 120.
And good luck making your darkroom - you can make just about anything work and it sounds like you have both ideas and skills. My darkroom has a water leak in the ceiling. I just work around it. As for electric, until I put an outlet in, I ran an extension cord under the door -- I have floor to ceiling black-out curtains between my workspace and the door, and just tucked a black towel over the small crack where the cord came in. Not pretty, but it worked.
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