It depends on whether you are going to change to fat bars..... I am and have ordered the 100 x 38/40mm pattern with matching 12mm bolt lower 1 3/4" clamp. They're modifying the top clamp to accept a 3 way rocker switch to suit my Symtec heated grips and I'm also adding a powerlet socket next to it
.
I'm sure and you should check with Paul from HDB that if you're keeping the 7/8 stock bars then you can keep the stock lower clamps and just order the 100 x 33/35mm top clamp.