I have a '91 Volkswagen Vanagon GL Campmobile.  I am considering installing a jump seat behind the passenger seat.  I have a few questions.

1.  Other than the bracket (the seller says it includes this) what do I need in the way of hardware for the installation?
2.  From other posts I have gotten the impression that a preferred way to fit the seat to the floor is to put hollow headed Allen bolts through the floor.  Can anyone refer me to more detailed instructions on this method.  With this method, is the seat solidly attached to the floor, or not?  Also, if there is a method that is as good or better, what is that, and where can I get instructions?
3.  Should I fit a three point seat belt to this seat, or just a lap belt?  Any pointers on doing that?  Someone a while back suggested that a 3-point belt fits ok and works.  Just attempting to confirm.

Thanks, David McNeely