I think you're right the tern panniers are short to suit their bike which will make them a bit short. Surly big dummy panniers would probably fit
but SWMBO had heel strike when I put the single panniers too far forward in the pic below. I'm thinking of getting a nice pair of Ortleib panniers for xmas & come up with a quick way to fit a crate to the rack, which worked ok for shopping trip on sunday - basically 5 standard shopping bags