If I can get out of meetings and dealing with regulatory agencies (the city was in today to inspect wastewater), I might actually have a chance to work on your seat! Fortunately, the injury rate is far lower than in years past!
With respect to the multi-groove pulleys, the easy route (albeit potentially more expensive) is to visit one's industrial power transmission shop. They can find the shaft diameter, offset, number of grooves, depth/contour of the grooves, etc. much more easily than we can use the Hollander interchange manuals to find what we are looking for.
As my "Professional" involvement in such engineering feats grows, the time I have to paw around boneyards has become non-existent (I have a Rangie being delivered this evening with electrical problems and oil leaks-can you say retirement!). Given the premium being placed on my time due to competing interests, it is more important to remember we are trying to drain a swamp, not conduct meaningless engineering exercises.
The days of my being able to cobble things together and then fine tune later are gone. It has to be either right the first time, or darned close.
Peace,
Paul