Sasuke's Legged Susanoo is equal to the BM avatar in stats, and possibly firepower, so I have the fight between them going either way but I can see an argument for Sasuke taking a majority since unlike Naruto he may not have a time limit.
The argument about Naruto's Yin-Yang cloak "heavily amping" Sasuke so that their avatars are far apart in power is easily debunkable.
1. The "Yin" portion of the cloak cancels out since Naruto also received Yin Kurama chakra from Minato, that in turn merged with the Yang chakra he had from Yang Kurama.
So it's more accurate to say that Sasuke was only additionally (relative to Naruto) by the Yang portion of the cloak, since both were amped by Yin chakra.
2. The cloak would need to scale to his Legged Susanoo, or above to amp it, and that's hardly the case given that only when Naruto heavily amped them and increased their sizes did they potentially even reach V3 level.
Sasuke's Legged Susanoo scales above a normal V3 as each Susanoo awakening carries more quantitatively more potent chakra than the previous. Sasuke's cloak wasn't even amped.
3. Naruto's chakra was split between 10000+ ninjas, meaning that each cloak represents about at best , if not even less than 0.01% of Kurama's chakra. If Sasuke, with 0.01% of Kurama's chakra can keep up with full BM, then he would only be 0.01% weaker without the cloak, and this is disregarding the fact that Sasuke's Legged Susanoo was amped by CS when it displayed relativity to the BM avatar, whereas the BM avatar was amped by Sage Mode, that scales above CS.
Overall, the BM avatar and the Legged Susanoo are fairly even in stats if we remove the amps for both. The only questionable metric is firepower, in which BM has more favorable feats due to TBB barrage and the supercharged variant.
However, the Legged Susanoo's arrow and the BM TBB were shown to be roughly on par when they've collided with Juubito's shield.
As such, fairly confident that Sasuke may be able to match supercharged TBBs with Enton or Raiton charged arrows, similar to how he matched the COFRS with his legless V3.
Overall, the fight can go either way extreme diff, but I favor Sasuke taking more Ws.
Madara actually says his V4 isn't his PS when asked if that was the case.
Look who's slow now.