Speed Unequalized, Sidious blitzes.
Speed Equalized... Oh boy, this is awesome. Yhwach is physically superior, has awesome hax, but I think that Sidious is even haxxier.
Supposing they go right to the kill, they would both be able to foresee the events that are going to take place, with Yhwach's precog being more efficient, but Sidious's ability to read minds being crucial to see Yhwach's attacks and techniques, and how they work. Their fight would be a continuous hax battle. Yhwach would use his casualty manipulation, Regenerationn and intangibility to good use, since I am pretty sure that Sidious is going to "destroy" him a lot of times via telepathy and akin. Eventually, Yhwach's going to figure out what Sidious is all about, and then, he can strike. Yhwach can kill Sidious with a strike, and with the Jail, the Visionary, the X-Axis and the Explode, I see that is completely possible, but even if his body is destroyed, Sidious's soul is going to live, and living, it would try to possess Yhwach's own.
But it still isn't over.
Considering Yhwach insane reiatsu, soul pressure and the fact he got the friggin' soul king, he should be able to fight off Sidious's possession, and eradicate him with his haxxier techniques. (Perhaps a reiatsu-based Kirchenlied: Sankt Zwinger)
The winner? Yhwach, with incredibly high difficulties.
Congratulations for that match. I'd pay to see that.