The first rule of power sources
Things which supply power must have female sockets, and things which draw power must have male plugs. The first corollary of that rule is that no cord may have male plugs on both ends. That is simply so the energy sources are always shielded (by virtue of the sockets being female). It's not any more complicated than that.
Now, what happens with a cord that is male plug at one end, and bare wires or lugs at the other? (e.g. typical dryer or range cord). Real simple: bolt it to the machine before you plug it into the wall.
Generally, if a person feels brutalized by incessant safety warnings from concerned citizens, it's because they have communicated loathing or alarming ignorance for the above rules or the electrical code generally. The best cure is to reduce the amount of "imagining rules" that you do, actively avoid sophomorism, and simply listen to best advice from the experienced.
Getting from "universal donor" NEMA 14-30 to 240V-only
The NEMA 14 series is the universal socket, because it provides neutral in case it is needed. What do you do if it isn't?
Really simple: you use a 3-wire cord that has a NEMA 14 male plug, and you don't hook neutral to any wire. The other end could be any of the following:
- Lugs for attachment to a machine
- A NEMA 6 family female socket
- a BS1363 female socket
- a CEE 6/3 female socket
- Etc. as meets your requirements
Now you have an "adapter cable" you can use for North American testing of the equipment. It connects normally and safely, either to the generator or hardwired NEMA 14 socket wired into the electrical grid.
"Why build a cord? Why not use a 4-wire cord and leave neutral flapping in the breeze? It's harmless." No, it's not. Neutral is insulated for a reason - a variety of faults can energize netural at line potential (120V or 230V). Eliminate it altogether from the cord.