Swapping 1986 four eye nose to 1991 notch..have question (bumper reinforcement)

I have a 91 notch and and swapping over the four eyed parts from a junker 1986 V6 LX hatchback.

I am having trouble figuring out how to get the 86 steel bumper to attach to my 91 impact absorbers. Ford changed the design in 1990 so I can't swap the impact absorbers easily. Here is the difference:



And here are the different mounts:

The 91:



or this (the 86 donor car):



Unfortunately, the bolt holes which hold in the absorber on the frame rail are not there. So I may just drill out the holes and be done with it. So the 86 absorber would go inside that box and the get fastened via a bolt like the previous design.

Another idea would be to use the 91 bumper absorber, drill a hole and depressurize it. Now its loose and could travel to any length I needed. Once it is at the correct length, I'll mark it and then weld it up. The holes which the actual bumper attaches to would need to be modified as the hole configuration is different.

Even another idea would be to use the fiber glass 91 bumper and modify the ends to accept the turn signals from the 86 bumper. I really like the fiberglass idea as the newer bumper reinforcement is significantly lighter in weight. But I don't even know if the fiberglass reinforcement will fit behind the 86 bumper cover.

Also, any interference with the airbag sensors? Looks like it will just about clear everything.

Thanks!