Dave,
Please explain with more detail the failure of the belts to hold tension. IIRC the lap and shoulder tensioners are different mechanisms entirely are they not? Lap belt tensioner is on the doorsill side reeling to the center, while the shoulder belt reels from the center? I believe I have all the belt and track mechanisms from my '93, in tan color if you determine what you may need. This image may help?
Heading up your way tomorrow to visit Sis in Tigard.
Glenn