seat bolts--1 more time

[Bullet]

i have an 04 SAN---the bolts holding the slide to the black riser that is mounted on the floor are loose----

i have tried to tighten them, but the nuts under the black riser won't tighten, they need to be back up---

i have tried prying the slider up while tighening--no luck

wonder if i can dremel a small hole into the riser to get a backup on it and tighen it?