-This is Obi Wan and Anakin as of their fight against Dooku on Oba Diah (so TCW5 I guess, but I'm not sure).
-This is Vos and Ventress as of their first fight against Dooku, in the first part of dark disciple.
Dooku was able to defend himself against both these duos with success, albeit both Anakin and Vos pressured him in the end. Imo Vos and Ventress's perfomance was better, but in theory Kenobi+Anakin should be a better duo.
Yep, Vos probably has the best performance against Dooku than any another character here (obviously RotS Anakin did better), but on the other hand Ventress should be the weakest here, so I thought it'd be pretty close
Obi-Wan takes out Ventress with medium to high difficulty.
We have a badass duel between S5 Anakin vs Vos as of DD. I give it to Vos based on his superior showing against Dooku than Anakin in his duel with Dooku in S5 (was that the one with Palpatine present? Because that's the one I have in mind). Not to mention Vos' Jedi Master level experience and maturity.
Then you have Obi-wan go up against Vos. At this point, Vos wouldn't have enough in the tank to beat Obi-wan. Obi-Wan is the only one left standing.
The weak link hear is Ventress. If we switched Obi-wan and Anakin's opponents, Obi-wan can duel Vos for a long enough time for Anakin to beat Ventress soundly. They both gang up on Vos and beat him.