Did you also try the j2A > ADjB > jA version, imo thats the easier version. Also, no one ever does the bnb #2 mentioned in the OP [starter] > Renka (1) > Gurren > IAD j.B > j.A, 5C, 2C > sj.B > j.2A, AD j.B > j.2A, j.C
Its not as good as the normal one since gurren may not bait bursts as well as kishuu but this version lets you practice the ADjB > JA part and also the 5C part thats used in the corner carry combos.