OK, this is posted for information, and something that I'm going top experiment more with - Film Scanning with the GFX (without a dedicated Macro lens) - these are my initial shots of film negatives using the GFX and a combination of GF45mm and GF63mm and 1 or 2 Viltrox 18mm Extension Tubes. These Extension Tuibes are a lot cheaper than the official Fujifilm one's and pass all signals through so will autofocus. I paid £90 each for mine (bought at different times) from eBayer sellers.
I have (at the moment) just placed the film on a Kaiser backlight, I have an Essential Film Holder on order, but these are made to order and I expect it in about 3 weeks. This will hold the film off the backlight and most importantantly hold it flat.
The GFX was mounted on a copy stand, and levelled using a spirit level.
The images presented are the full GFX filed of view though I have cropped the 6x6 image to square. This gives me more than enough resolution to print big (though the 35mm image will have fallen appart long before then - I still deciding if shooting 35mm film is actually for me, and whether I should just switch to MF only) - The Images were imported into LIghtroom and then processed using Negative Lab Pro.
GFX50S + GF63mm + 1x18mm Viltrox Extn - 6x6 film
GFX50S + GF63mm + 2x18mm Viltrox Extn - 645 film
GFX50S + GF45mm + x18mm Viltrox Extn - 35mm film
My first impressions are, that it a lot easier than scanning, and the quality of the 35mm negative is much better with this method than my Epson V600 - it definitely wants more experimentation, I need to get the film holder, and darken the room when taking the image, and look into thering the camera so I can get the image straight into Lightroom - I've had some good MF scans from the Epson scanner, but I think this setup has the potential to be better.