Paul  ...the minimum distance on your by-pass would be FMU (fitting make-up) a red tee or WOL with an elbow. You my have to stagger the valves so it will fit, but that should work. Hard to tell for sure, you didn't indicate the rating of the pipeline. the NORMAL rule of thumb is 1" clearance between the edge of a flange and side of a pipe for line spacing in a pipeway, but just for clearance it should be at least 3" for maintance operation. Hope this helps  ...Mark