I am building my 4" Durham to the series in model engineer. The fork ends on the reach rods at the opposite end to the eccentric straps look to be set 3/64" to one side of centre looking down and possibly handed.
Do you mean the eccentric rods as the reach rod usually goes from reversing lever to lifting link?
If it is the eccentric rods then there is usually an off set in one or both as the forks need to end up vertically above each other so they slip onto the expansion link. Total of the offsets including any where they join the eccentric strapgenerally equals width of one eccentric width.