Hi and thanks for the feedback.
In your proposed setup, I suspect the 3800/3880 would end up unspooling your entire roll, because it will treat the whole thing as a big sheet. It doesn't "know" in advance where the end is.
Just checked with the RIP makers... and my RIP will not support stopping the printer from feeding the paper after a finished print.
So unless there is a way to disable the whole roll to get feed through the printer I will have to cut before each print job.
And... I'm not going to buy a RIP from someone else.
If someone has a clue on how to stop the printer from feeding untill end of paper after print has finished (without buying another RIP that is), then I hope they can post it here.