Personally, I don't like ripping, you can end up with waves and still have to clean-up edges. If you happen to have access to a long t-square that's what I would use, I stole mine from my husband. When I have to do borders really long and don't want to fold my material numerous times I pull out my 48" t-square. Then I have maybe 1-2 folds to cut through. Works well.
Good Luck!!