I'm no expert with enclosed driveshaft rearend housings - but, you will have to get that 1/4" of movement fixed or the truck will not drive well at all. I see your dilema with filing the saddles, to get rid of that much play will produce "egg shape" that will wear very fast. If you can measure the housing diameter where saddles attach - see if it is round. Then have your local machine shop mill the saddle halves and rebore to sliding fit of axle housing diameter. Just my thoughts - good luck, let know how you solved the issue.
