Thanks for your opinions
Grunfeld vs 1.Nf3/1.c4

I'm not entirely sure how to answer the question, mostly to do with the fact that I don't have a whole lot of experience, but if you're asking how to transpose to or play a grunfeld like position, I think you'll have a hard time doing so against 1.Nf3/1.c4. From what I understand, a lot of the time, these moves are played to avoid the grunfeld entirely.
Good luck on your search! Hopefully you'll find an answer to the question you're asking. Sorry I couldn't be more help!
It's been said that hindering the grunfeld is one reason for the number of English's in the recent Candidates. Maybe the many transpo chances can give black at least a psychological plus. I offer to steer 1. c4 towards a QGD or Catalan with ...e6 and if 2. e4 c5 with maybe some kind of maroczy Sicilian or as you mentioned some sort of closed center though I'm not sure if the open e5 is a plus or minus for black.

The Fianchetto System
1.d4 Nf6 2.c4 g6 3.g3 Bg7
3...c6 4.Bg2 d5 5.Nf3 Bg7 6.b3 (6.cxd5 )
4.Bg2 d5 5.Nf3
5...dxc4 6.Na3 c3 7.bxc3 c5 8.0-0 0-0 9.Ne5
9.Nc4
9.Qb3
9.e3 Nc6 10.Qe2
(10.Bb2 ) 10...Nd5 11.Bb2 Nb6 12.Rfd1
12.Rab1
12.Rac1
12.Rad1
5.cxd5 Nxd5 6.e4 (6.Nc3 ) 6...Nb6 7.Ne2 (7.Nf3 ) 7...c5
8.d5 0-0 9.0-0 e6 10.Nec3 Na6 11.a4 (11.Nd2; 11.Na3 ) 11...Nb4
10.Nbc3 Na6! (10...exd5 ) 11.Nf4 e5
11.h3
11.Bf4
11.b3
6.Nf3 Nb6 7.Nc3 (7.0-0 Nc6 8.Nc3 ) 7...Nc6
8.e3 0-0 9.0-0 Re8 (9...e5; 9...a5 )
10.d5
10.Re1 a5 (10...e6!? )
11.Qc2
11.Ng5
11.b3
11.Qd2
11.a4
11.d5
11.h3
11.Nd2
11.Qe2
The Bf4 System
1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.Bf4 Bg7 5.Rc1
5.Nf3 0-0 (5...c5? 72) 6.e3
6.Rc1 c5
6...dxc4
5.e3
5...c5 6.cxd5
6.Rc1
5...c5 6.dxc5 Qa5
7.Qb3
7.Qa4+
7.Nf3
7.Rc1 dxc4 8.Bxc4 (8.Qa4+ ) 8...0-0 9.Nge2 Qxc5 10.Qb3 Qa5 10...Nc6
Systems with Bg5
1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.Bg5 Ne4 5.Bh4 (5.cxd5; 5.Bf4; 5.Ne4; 5.h4!?)
5...Nxc3 6.bxc3 dxc4 7.e3 (7.e4 ) 7...Be6
8.Be2
8.Qb1
8.Rb1
8.Nf3 Nd7 9.Be2 (9.d5; 9.a4 ) 9...Nb6 10.0-0 Bg7 11.a4
11.e4
4...Bg7 5.Bxf6 (5.Nf3 ; 5.e3 c5 ) 5...Bxf6 6.cxd5 c6
7.dxc6
7.e3
7.e4
7.Rc1
4.Nf3 Bg7 5.Bg5 Ne4 6.Bf4
6.cxd5 Nxg5 7.Nxg5 0-0 (7...c6 )
6.Bh4 Nxc3 7.bxc3 dxc4 8.Qa4+
The e3 System
1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.e3 Bg7 5.cxd5 Nxd5 6.Nxd5 (6.Bc4 )
5.Qb3 dxc4 6.Bxc4 0-0 7.Nf3 c5 8.d5 (8.dxc5 )
5.Nf3 Bg7 6.Bd2 (6.cxd5; 6.Qb3 )
6.b4
6.Be2 c5 7.dxc5
7.0-0
The English Anti-Grünfeld
1.c4 Nf6 2.Nc3 d5 3.cxd5 Nxd5 4.g3 g6 5.Bg2 Nb6 6.Bg2 Bg7 7.Be3 Nc6
8.Qd2
8.Bxc6+
8.Qc1
8.Rc1
8.Nf3 0-0 9.0-0 (9.Qc1, 9.Qd2 ) 9...e5 (9...Re8 ) 10.Qd2
10.Rc1
10.a4
10.Qc1
10.b4
1.Nf3 Nf6 2.c4 g6 3.b4
1.Nf3 Nf6 2.c4 g6 3.Nc3 d5 4.Qa4+ (4.cxd5 Nxd5 5.Qa4+)
4.cxd5 Nxd5 5.Qb3 (5.e4 ) Nb6 6.d4
1.d4 Nf6 2.Nf3 g6 3.Nc3 d5 4.Bf4
Anti-Grünfeld with 3.f3
1.d4 Nf6 2.c4 g6 3.f3
3...Nc6 4.d5 Ne5 5.e4 d6 6.Ne2
6.f4
6.Nc3
4.Nc3
4.e4
Odd Systems
1.d4 Nf6 2.c4 g6 3.Nc3 d5
4.g4?!
4.h4?!
4.Bg5 Ne4 5.Qc1
5.h4!?
4.cxd5 Nxd5 5.e4 Nxc3 6.bxc3 Bg7 7.Bg5
1.Nf3 N6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5 5.h4!?
The Exchange System with 7.Bc4
1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5 5.e4 Nxc3 6.bxc3 Bg7 7.Bc4 0-0 8.Ne2 c5 9.Be3 Nc6 10.0-0 (10.Rc1) 10...Qc7 (10...e6 ) 11.Rc1 (11.Bf4; 11.d5; 11.Qc1; 11.Rb1; 11.h3 ) 11...Rd8 (11...
e6 )12.f4 (12.d5, 12.h3; 12.Qe1, 12.Qa4 ) 12.Qd2 a6 (12...Qa5 )
12.Bf4 Qd7 13.dxc5
13.d5
Rare Systems
1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5 5.e4 Nxc3 6.bxc3 Bg7
7.Bb5+
7.Qa4+
7.Ba3
7.Bg5
Rare Systems
1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5
5.Bg5
5.Bd2 (4.Nf3 Bg7 5.cxd5 Nxd5 6.Bd2 ) 5...Nb6 (5...Bg7 ) 6.Nf3
6.Bg5
6.Bf4
5.Na4
5.Qb3 Nxc3 6.bxc3 Bg7 7.Ba3
7.Nf3
The Qb3 System
1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.Nf3 (4.Qa4+ ) 4...Bg7 5.Qb3 dxc4 6.Qxc4 0-0 7.e4 Nc6 8.Be2 (8.d5, 8.Be3, 8.e5, 8.Bf4, 8.Bg5) 8...Bg4 (8...e5 ) 9.d5 (9.Be3 ) 9...Na5 10.Qb4 (10.Qa4 ) Bxf3 11.Bxf3 c6
12.Be3
12.0-0 Qb6 13.Qa4 (13.Qxe7; 13.Qxb6 ) 13...Nd7 14.Qc2
14.Be3
14.dxc6
14.Be2
14.Rd1
The 7.Be3 System
1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5 5.e4 Nxc3 6.bxc3 Bg7 7.Be3 c5 (8.Nf3; 8.Bc4)
8.Qd2 cxd4 9.cxd4 Nc6 10.Rd1 0-0 11.Nf3 (11.d5; 11.Be2 )
8.Rc1 Qa5 9.Qd2 0-0 10.Nf3 (10.Bc4 ; 10.d5 )
The Exchange System with 7.Nf3
1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5 5.e4 Nxc3 6.bxc3 Bg7 7.Nf3 c5
8.Bb5+
8.Be2
8.h3
8.Be3
8.Rb1 0-0 9.Be2 Nc6 10.d5 (10.Be3 cxd4) 10...Ne5 11.Nxe5 Bxe5 12.Qd2 (12.Rb3, 12.Bd2, 12.c4) 12...e6 13.f4 Bc7 (13...Bg7) 14.0-0 (14.Bc4) 14...exd5 15.exd5 Ba5
16.g4
16.Rb5
16.Rb3
16.Ba3
16.f5
16.d6
9...b6!?
I usually play the KID but I'm lately thinking to switch to the Grunfeld. The problem is I don't know what to play against 1.Nf3/1.c4. With the KID is easy to play against the flank openings. Not so with the Grunfeld. I've read somewhere that what you play against the English has to do with what you play against the Fianchetto System. In the Fianchetto Grunfeld I like to play a quick d5 but I'd play c6 and d5 systems if that makes my life easier vs the Flank Openings.