A difficult topic to answer. I would say that Sasuke's chakra reserves are definitely not above average. That would be quite wrong as kakashi in part first made explicit comparisons between his own Chakra reserves and then Sasuke and Naruto's. Then one can recall that how surprised he was that a genin would not have enough chakra for that katon attack at all.
All this and the recent feats point towards pretty good, if not large chakra reserves. Now, keep in mind then that term 'large' is quite relative in Naruto. Now Naruto's chakra reserves at base level are about five times higher than Kakashi as put by kakashi himself during the training. Let's not count Kurama's chakra as Naruto's own, shall we? And yet, Kakashi's chakra reserves are quite average if one goes by his own statements.
Fourth Raikage or Raikage's in general have more Chakra reserves than Naruto, which is a certainty. Their Raiton Armour is the same as Nagashi, but they are able to create Full Armours as they have very large chakra pools. As fourth Raikage's is equivalent to Bijuu level - Karin points it out when he upped his aromour to V2 - and same is the case with Kisame, and Hashirama's were probably bottomless. You cannot compare Naruto's chakra reserves to these people.
So as evidence points out, as base level, Sasuke's are not at Naruto's level but would not be far below him either given the very first juxtaposition between their reserves. That is what I firmly believe.
