Honestly, we havent; the foggiest of what you want to do.

The generator probably has a 50 ohm output. If it's an FM radio, the input is likely 75 ohms. So, you do need a matching transformer. So, there's generally BNC to BNC and an F connector at the receiver. You can buy adapters to adapt the BNC to F. or BNC to quick F.

RG-58 isn't terribly inflexible. If you want flexibility, then RG174 should work.

At one point, at work we had lots of crimped BNC cables, bought from a reputable manufacturer. Nearly all failed at one point. the broken ones were eventually fitted with clamp BNC plugs. They are not the easiest things to put together, but a resistance soldering tool made it a lot easier.

It also depends where you want to put the adapters.