Seat relocation brackets

Hello,
Has anyone used the Year one seat relocation brackets?
1966-74 A B E-Body Universal Seat Relocation Brackets
I would like to use them in my 68 Valiant (bench seat) but am trying to get my head around how they would work.
The last time I removed the bench seat I found that the bolts on the seat that go through the floor were quiet long so I don't know how this would work with Year ones brackets.
Unfortunately they don't list any instructions on their website so if anyone has used them please let me know how you went.
Thanks,
Ron