This is ROTS Obi-Wan and Kopecz in from PoD. I think this would be pretty close, in PoD Kopecz did something similar to what Kenobi did at the beginning of ROTS, flew his starfighter into the hanger of an enemy ship, jumped out before the ship came to a stop, and slaughtered all the droids/republic sopldiers in the hanger (in Kopecz's case his starfighter had already ran over most of them). PoD calls Kopecz and Qordis "two of the more powerful Sith Lords". Bane had been able to feel Kopecz's commanding presence even through a containment field (this was before he had received any training). Physically he has Obi-Wan: "Even under the loose-fitting robe he wore, Des (Bane) could see he was thick and heavyset. He stood nearly two meters tall, easily the largest Twi’lek Des had ever met… though not quite as large as Des himself."

On the enemy ship, after jumping out of his ship in the hanger, he was intercepted by a security team. "The red badges on their sleeves marked them as an elite squad of specially trained soldiers: the best bodyguards the Republic military had to offer. Kopecz knew they must have been good…one actually managed to fire her weapon twice before the entire unit fell to his lightsaber.

Then he pwns two Padawans instantly, using only the Force.

Then, at the end of the book, when Kopecz is so injured that he doesn't have long to live, he fights Farfalla and though he was no match for the fresh and uninjured Jedi he put up a valiant fight.

To me Kopecz seems stronger with the Forcw, pwning Padawans and all, but Kenobi is probably better with a lightsaber. I'd put Kopecz as only behind Bane and Kas'im for his era. Overall I'm really not sure, he'd probably choose to engage Kenobi in a saber duel but if he started to lsoe he could always whip out the Force on him, though I'm not sure it'd be enough. I don't know.