I never played / tested fiber optics, only coax cable,although now internet these days are fiber opttcs laying around the floor hidden in furniture
I've used in work some equipment with fiber optics but on the software / firmware side and with heavly warning about do not touch this cable
About attenuation i mispoke ou speak poorly my english , the sentence is a mess indeed. I wanted to say it had less amplitude . The better sample rate and probes refers to the results about the TOF values on the 8500A.
Machining a block thats a neat idea, time consuming. The other way could be modeling clay but that would take a while to dry.
Now about handheld robustness. My cheapo 10 euro mini tool busted affter 2 years and 1 month after waranty
it smoked and stopped working. I open the brushes compartiment and one metallic tab was broken as well the spring. there was also something rattling inside and had to open the tool to remove the remainings of the spring.... I attached another spring to the breaked one and works good with low loads such as plastic.