I needed 2 x 0.5mm nylon spacers (these were supplied with my 3DF cranks) and a turn on the pre load adjuster
And did your manual mention something about spacers? I measured the gap you can see in the 2nd photo and its about 5mm.. So the nylon spacers won't be enough.
The 3D+ manual has a single 0.5mm spacer between the pre load adjuster and the bearing - I don't think there is a manual specific to the BSA30 adapter.
Have you measured your BB shell width? I don't think there's a problem with using spacers, but you'll need to maintain the correct chain line or you may run in to shifting issues.