Front wheel bearing spacer size

[TFR Aussie]

I'm replacing the front wheel bearings on my 1975 XS650B twin disc model and wanted to know what length the internal spacer should be as I found a shim in there that's not in any part book.

I get 68.5mm and the extra shim between the spacer and bearing is 1mm thick. Should it be 70mm?

I have had binding issues with the wheel binding and the brake calipers not being centred on the disc.