Historically. How did someone engage in a duel wielding a scimitar? It's really hard to find an answer online about fencing techniques used with curved swords that isn't the fantastic whirling dervish technique.
I've run into the same problem when trying to find out more information on how Byzantine soldiers wielded the paramerion. As far as I can tell, there is virtually nothing written on the subject. In the case of your weapon, however, it may just be a result of poor cultural diffusion of sources and discussion. At the very least I have seen some videos on YouTube featuring Middle Eastern weaponry and referencing some obscure combat manuals.
One thing that I have tried to do to solve my problem is to look at fencing techniques for various cavalry sabres as well as the techniques for the Grosse Messer, which both were rather similar in design. By looking at these techniques, it might be possible to get an idea of how both the paramerion and the scimitar were used. Perhaps doing something like this might help you to gather more info.
During your search, keep in mind that the scimitar, the talwar/tulwar, the kilij, and the shamshir are all virtually identical, so try searching for those too and you might find some new leads.