I also heard that Chandran ring signatures are significantly larger than the already large ring signatures used by cryptonotes with typical real world mixin values of 3-10, is it true?
No. The signatures to be implemented in SteathSend are 1/3 or the size of those used in Cryptonote coins. That is the whole point. This will become clear when the white paper is released a few days before SteathSend goes live.