I just stick them in the sides also.
To solve the problem of safety, I got a seat from a pre-92 Bronco. I got one from an 87 model but they are all interchangeble from 1980-1996. Cost me $20 at a local "pick and pull". The older seats have three lapbelts mounted directly to the seat so there is no excess material to deal with and you can be sure that all three passengers back there are safely and sucurely strapped down.
Here are the 96 and 87 seats next to each other, you can see the one on the right has all the seatbelt parts attached to it:
Can't even tell that it is not original to the truck:
Best part was the price: