I'm not sure a G5 roll now can be continued upon in the new version, as the mod is grandfathered. You may lose the entire effect of the curent mod and need to reroll from the start none-the-less. So I would not bet on them being transferable.
Just do a single G5 roll unless you plan to keep the modules as-is and presume the worst. Also remember that having the new storage means you can keep all the stuff you would normally toss, and get a lot of low grade rolls "for free" this way. I actually have no problem with needing to reroll from the start on new modules, as all the G1/G2/G3 mods are easy to get materials that you scoop up looking for the rarer stuff anyway. Just do a few Dav's Hope runs and you will have 100 each of the none-rare items in an hour or so.
Any G5 mod will become the highest rated G4 mod if you re-roll it. Otherwise, it's grandfathered as is.
You will only be able to trade materials within a class and at a loss. So you won't be able to gather a bunch of common mats and exchange them for rares.
https://forums.frontier.co.uk/showt...ETTER-FUTURE?p=6177830&viewfull=1#post6177830