User blog comment:LittlePeng9/SCG(1)/@comment-5529393-20130313042828/@comment-5529393-20130313080934

Well, SSCG(3) is much larger than TREE(3), or even TREE^n(n) for any reasonable n. Since SCG(1) is much, much larger than SSCG(2), I would have bet that SCG(2) would be larger than SSCG(3). But I don't see an obvious way to embed labelled trees into the sequence for SCG(2).