Installing bed wood kit on a 71 long/fleet

[gonline71]

I have already dry fit the bed and marked the outside hole locations. My question is this, where do I drill the holes for the long carriage bolts that mount to the frame? I have scoured Horkey's, Mar-K, Brother's LMC....and have found conflicting info. Before I make an assumption and mess this up....is there standard location or can I just put them wherever the cross sill attaches to the frame? What about the last cross sill at the tail gate....are those two I should be using? It has been so long since I removed the original bed, I cannot remember what went through those nearest the tail gate.

Thanks in advance