Take the roamer seed from timefinder, put it in the main window of rng reporter, change the type to "wild encounter", pick a nature on a frame about 650+, change it back to "roaming", see if the same nature is a few frames away. If not keep looking until you find a match.
Ie my roamer seed had a Naive nature on frame 635 for wild pokes. Then I switched it to roamers and it was on frame 638. Once you find a match just go to Pandora's box, look at some IDs they give you, test each one and see if the frame is shiny for the roamer.