Just use the plates to set the distance for the support,
You might need to alter the angle where they meet the top rail & the tranny tunnel tho,
Set the plates 60mm apart & then you will find the bracket from your steering column will fit nicely
Whilst the support is critical to the steering column, the height of it isn,t as there is loads of space under the scuttle , just make sure its level.
hope this helps.
cheers
andy