I put my 929 shock into my 5th gen today. I used part of a 1/4" x 1 1/4" kart axle for the spacer, and made it 45mm longer than stock including the washer. Heavy and not as elegant as some of the other beautiful spacers people have made, but I'm way more overweight than the bike anyway. Plus I only spent $35 for the shock and 3/8 grade 8 hardware.
Due to the larger diameter spacer, I had to grind a little notch in the top of the spacer to clear the protruding angle in the frame rail. No clearance issues. I rode about 15 miles this am, starting with the preload on the 3th increment from max, with damping set in the middle on both comp. and rebound. So far seems like an improvement in ride quality and control compared to the old stock shock.