There were people who think that using RSW to spar cannot do the same line control as the steel sword, since any impact feels different. I did a test side by side, with RSW katana and RSW longsword, as well as a hanwei katana and a windlass 15th century longsword.

I used the katana tip to hit the other sword, with single hand, since my other hand was holding the cam.

On the side to edge impact, it shows that it was exactly behaving the same. On the edge to edge impact, I screwed up the steel part since the windlass 15th century longsword has side rings. The katana's strikes get distracted by the side rings. Still one can see that the result is pretty close despite of that.

Thus using RSW to practice swordsmanship not only allow ones to Fa Ging in the strike but can simulate very well how a steel sword would do in safety.

https://youtu.be/AHsXDkw8xNc