The long spacer (LHS) is 55mm in length
The short spacer (RHS) is 30mm in length
Stud is 12mm OD
Front spacer is not circular but a horseshoe shape and is 4.5mm thick
Rear bracket before paint is 4.5mm thick (the one pictured with the stop switch mount)
AL
P.S.
My No. 4 exhaust header is dangerously close to the front frame tube so it has to be dead right or better!!!