The OP is doing it all wrong. Quit thinking of it as playing Black and playing White.
You need to figure out a cohesive set of openings that you UNDERSTAND. Not understand the White Side or the Black Side. Flat out understand!
Every opening that I play I could play as Black or White. Some of them I don't because they allow other openings I look to avoid. This is where the fact that they need to be cohesive comes into play. Also, because there is one opening, no matter how you set your repertoire up, where you will have to play it as both Black and White, it should be the opening you know completely inside and out.
Example. Take myself.
Opening I know inside and out - French Defense. Therefore, this is likely to be my overlap.
Other Openings or Specific Variations I know:
Berlin
Petroff
Italian
Advance Caro
Fantasy Caro
Closed Sicilian
Maroczy Bind Structures (Kalashnikov, Accelerated Dragon, Princeton, etc)
QGA
QGD
KID
NID
...e6 Dutch lines (Classical and Stonewall)
English Opening
Sokolsky
So let's look at this:
I can easily go Italian as White as I also understand the Petroff (not worried about minor, inferior lines like the Philidor via 1...e5 - Hanham can be avoided that way).
Closed Sicilian. I could play that as Black, and have transposed to it as Black on Defending the Bird (1.f4 Nf6 2.Nf3 g6 3.g3 Bg7 4.Bg2 d6 5.O-O c5 6.d3 Nc6 7.e4 etc.). But I would not play it as Black against 1.e4 as it allows the Open Sicilian. So I would only play this with White, but am fully capable of playing either side of it because I studied the opening, not just memorize White's moves.
Advance or Fantasy against the Caro.
French of course from both sides
Against 1.d4, I have to pick an opening I understand.
But notice how I have landmines that I avoid:
Sicilian Dragon
Grunfeld Defense
Modern Benoni
Reti
But by not playing the Open Sicilian as White or else playing 5.f3 in 2...d6 Sicilians, 1.e4 is a safe route to take.
1.d4 would not be smart because Black can play the Grunfeld or Modern Benoni.
However, 1.Nf3 is fine as I can play an anti-grunfeld and only allow the Kings Indian (1.Nf3 Nf6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5 5.e4 Nxc3 6.dxc3 - 6.bxc3 followed by 7.d4 would be back in the Grunfeld) via 1.Nf3 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 and only then 5.d4. No Grunfeld. Also no Benoni, with an early ...c5, Symmetrical English. 1.Nf3 d5, 2.d4 and no Grunfeld as 2...Nf6 3.c4 g6 4.cxd5 Nxd5 5.e4 is just bad for Black as he cannot trade on c3.
I could also play 1.b4 and do occasionally.
I do play ...d5 lines as Black, but only against 1.d4. I play the QGA (1.d4 d5 2.c4 dxc4) not allowing cxd5 lines. I also avoid the Reti, so no 1.c4 e6 2.Nf3 d5 or 1.Nf3 d5 2.c4. Instead, I go 1...f5 against 1.Nf3 or 1.c4. White can play an early d4 and go into a Dutch, but I am fine with that.
So by knowing what you actually understand, and knowing which openings to avoid personally (for me, that is the Dragon, Grunfeld, Modern Benoni, and Reti), you can put together a cohesive repertoire. Like below is mine right now (repertoire can change over time):
White - 1.e4, 1.Nf3, 1.c4, 1.b4
Black - French, QGA, Classical Dutch, early ...f5 with ...e5 to come against Flank Openings (i.e. 1.c4 f5 2.g3 Nf6 3.Bg2 d6 and now 4.d4 e6 is a Classical Dutch and 4.Nf3 or 4.Nc3 allows 4...e5. Same against 1.Nf3. 1.Nf3 f5 2.g3 (2.d3 Nc6) Nf6 3.Bg2 d6 and now 4.d4 e6 (Dutch) or 4.c4/4.O-O and I reply 4...e5, the move 1.Nf3 was intended to avoid.
This is how you need to approach it. Not just play random moves waiting for the opponent to castle. For example, on the French, Black often delays castling as long as possible!
thks for the leson