Glad you could use the speedo information. As for the fuel sender, the data I provided to your question via the Jensen Mail List (i.e. circa 30 ohms full tank, to circa 370 ohms empty tank) is probably the standard industry spec for the part. I researched all that some years ago, and while I don't recall the details, I do recollect that there are perhaps a dozen different specs in current use, including two that call out identical endpoint resistance values but radically different curves. So approach replacement senders with caution.
For exact measurements, the sender in my car measures 20.9 ohms full, 81.1 ohms half, 241.4 ohms empty, with the sender installed in the fuel tank. It is easily possible to vary this by 20% or more through altering the bends applied to the float rod. There may also be a mechanical stop on one or both ends of the rod's swing, and if so, this/these too could also affect readings (don't recall, and the photos I have aren't clear).
Even with decent quality control for these parts, I'd expect to see individual units vary in resistance by as much as 5%, without taking into consideration any variations in the float rods or mechanical stops.
So in the final analysis, if you can't find an exact replacement part, find a sender having the proper endpoints, more or less, and tweak things until your gauge performs acceptably.