The doctor is in the house
Having owned and used professionally: three different horribly expensive drum scanners, a Nikon Super Cool Scan 9000 ED, an Epson V750 and several other scanners over the years, I feel pretty confident that I can give you some good advice here.
First, buying an accurate light box and decent loupe is very advisable to pick your winners to scan and winnow out the rest. You don't need the very best loupe and it doesn't need to "see" the whole 6x7cm area at once. Buy a cheap large round glass magnifying lens with handle to examine the whole image at once - maybe a 3x or 4X model - for composition and exposure. To examine it for critical sharpness, you need a quality loupe, but it needn't cover the whole image; you can move it around to check critical sharpness. A good quality 6X to 10X loupe meant to cover 35mm, used, should be pretty reasonable, much cheaper than one made to cover 6x7. Next, the box. Definitely try to find an old, even fairly beat up, box of good quality, a true 5000K photo lightbox, such as a Graphic Lite or Acculight, or even an old MacBeth (Gretag/Xrite), and you don't need one bigger than about 12"x12" either. Just clean the heck out of the plastic diffuser (discard and replace if it is visibly yellow) and replace the special fluorescent lamp(s) if it has been used for a very long time as is. Don't try to save money by buying what amounts to a tracing table instead. You can also find some very good deals on newer, but still used, ultra thin profile (LED lit) 5000K lightboxes built by serious companies like Cabin; these are "good enough."
As to a scanner, either buy a used Nikon 8000 or 9000 Coolscan or an Epson V700/V750; don't waste your time on anything else for 6x7 film. If you want a drum scan, depending on the scanner and operator, they can produce better, sharper and bigger scans. But a good operator with a Nikon 9000 can deliver a scan as good or better than one from a top rated Heidelberg or Crosfield or ICG or Screen drum scanner, made by a mediocre or indifferent operator. So, know your supplier, and when and if a very special scan is necessary for an extremely big enlargement, or from a very difficult, contrasty or poorly exposed original, you can exercise the drum scan option. For literally 90% or more of professional or passionate amateur work, the output from a Nikon 9000 or an Epson V750, made by a truly competent operator, will be more than sufficent.
Good luck in finding your gear. You will find that a good 6x7 scan is a beautiful thing, and learning to make it is not that hard and, eventually, even a lot of fun.